src/HOL/Nominal/Nominal.thy
 author narboux Tue, 24 Apr 2007 14:02:16 +0200 changeset 22775 d08efe73b27f parent 22774 8c64803fae48 child 22785 fab155c8ce46 permissions -rw-r--r--
oups : wrong commit
```
(* \$Id\$ *)

theory Nominal
imports Main Infinite_Set
uses
("nominal_thmdecls.ML")
("nominal_atoms.ML")
("nominal_package.ML")
("nominal_induct.ML")
("nominal_permeq.ML")
("nominal_fresh_fun.ML")
("nominal_primrec.ML")
("nominal_inductive.ML")
begin

section {* Permutations *}
(*======================*)

types
'x prm = "('x \<times> 'x) list"

(* polymorphic operations for permutation and swapping *)
consts
perm :: "'x prm \<Rightarrow> 'a \<Rightarrow> 'a"     (infixr "\<bullet>" 80)
swap :: "('x \<times> 'x) \<Rightarrow> 'x \<Rightarrow> 'x"

(* for the decision procedure involving permutations *)
(* (to make the perm-composition to be terminating   *)
constdefs
"perm_aux pi x \<equiv> pi\<bullet>x"

(* permutation on sets *)
perm_set_def:  "pi\<bullet>(X::'a set) \<equiv> {pi\<bullet>a | a. a\<in>X}"

lemma empty_eqvt:
shows "pi\<bullet>{} = {}"

lemma union_eqvt:
shows "pi \<bullet> (X \<union> Y) = (pi \<bullet> X) \<union> (pi \<bullet> Y)"

lemma insert_eqvt:
shows "pi\<bullet>(insert x X) = insert (pi\<bullet>x) (pi\<bullet>X)"

(* permutation on units and products *)
primrec (unchecked perm_unit)
"pi\<bullet>()    = ()"

primrec (unchecked perm_prod)
"pi\<bullet>(a,b) = (pi\<bullet>a,pi\<bullet>b)"

lemma fst_eqvt:
"pi\<bullet>(fst x) = fst (pi\<bullet>x)"
by (cases x) simp

lemma snd_eqvt:
"pi\<bullet>(snd x) = snd (pi\<bullet>x)"
by (cases x) simp

(* permutation on lists *)
primrec (unchecked perm_list)
nil_eqvt:  "pi\<bullet>[]     = []"
cons_eqvt: "pi\<bullet>(x#xs) = (pi\<bullet>x)#(pi\<bullet>xs)"

lemma append_eqvt:
fixes pi :: "'x prm"
and   l1 :: "'a list"
and   l2 :: "'a list"
shows "pi\<bullet>(l1@l2) = (pi\<bullet>l1)@(pi\<bullet>l2)"
by (induct l1) auto

lemma rev_eqvt:
fixes pi :: "'x prm"
and   l  :: "'a list"
shows "pi\<bullet>(rev l) = rev (pi\<bullet>l)"
by (induct l) (simp_all add: append_eqvt)

lemma set_eqvt:
fixes pi :: "'x prm"
and   xs :: "'a list"
shows "pi\<bullet>(set xs) = set (pi\<bullet>xs)"
by (induct xs, auto simp add: empty_eqvt insert_eqvt)

(* permutation on functions *)
perm_fun_def: "pi\<bullet>(f::'a\<Rightarrow>'b) \<equiv> (\<lambda>x. pi\<bullet>f((rev pi)\<bullet>x))"

(* permutation on bools *)
primrec (unchecked perm_bool)
true_eqvt:  "pi\<bullet>True  = True"
false_eqvt: "pi\<bullet>False = False"

lemma perm_bool:
shows "pi\<bullet>(b::bool) = b"
by (cases b) auto

lemma perm_boolI:
assumes a: "P"
shows "pi\<bullet>P"
using a by (simp add: perm_bool)

lemma perm_boolE:
assumes a: "pi\<bullet>P"
shows "P"
using a by (simp add: perm_bool)

lemma if_eqvt:
fixes pi::"'a prm"
shows "pi\<bullet>(if b then c1 else c2) = (if (pi\<bullet>b) then (pi\<bullet>c1) else (pi\<bullet>c2))"
done

lemma imp_eqvt:
shows "pi\<bullet>(A\<longrightarrow>B) = ((pi\<bullet>A)\<longrightarrow>(pi\<bullet>B))"

lemma conj_eqvt:
shows "pi\<bullet>(A\<and>B) = ((pi\<bullet>A)\<and>(pi\<bullet>B))"

lemma disj_eqvt:
shows "pi\<bullet>(A\<or>B) = ((pi\<bullet>A)\<or>(pi\<bullet>B))"

lemma neg_eqvt:
shows "pi\<bullet>(\<not> A) = (\<not> (pi\<bullet>A))"

(* permutation on options *)

primrec (unchecked perm_option)
some_eqvt:  "pi\<bullet>Some(x) = Some(pi\<bullet>x)"
none_eqvt:  "pi\<bullet>None    = None"

(* a "private" copy of the option type used in the abstraction function *)
datatype 'a noption = nSome 'a | nNone

primrec (unchecked perm_noption)
nSome_eqvt: "pi\<bullet>nSome(x) = nSome(pi\<bullet>x)"
nNone_eqvt: "pi\<bullet>nNone    = nNone"

(* a "private" copy of the product type used in the nominal induct method *)
datatype ('a,'b) nprod = nPair 'a 'b

primrec (unchecked perm_nprod)
perm_nProd_def: "pi\<bullet>(nPair x1 x2)  = nPair (pi\<bullet>x1) (pi\<bullet>x2)"

(* permutation on characters (used in strings) *)
perm_char_def: "pi\<bullet>(s::char) \<equiv> s"

(* permutation on ints *)
perm_int_def:    "pi\<bullet>(i::int) \<equiv> i"

(* permutation on nats *)
perm_nat_def:    "pi\<bullet>(i::nat) \<equiv> i"

section {* permutation equality *}
(*==============================*)

constdefs
prm_eq :: "'x prm \<Rightarrow> 'x prm \<Rightarrow> bool"  (" _ \<triangleq> _ " [80,80] 80)
"pi1 \<triangleq> pi2 \<equiv> \<forall>a::'x. pi1\<bullet>a = pi2\<bullet>a"

section {* Support, Freshness and Supports*}
(*========================================*)
constdefs
supp :: "'a \<Rightarrow> ('x set)"
"supp x \<equiv> {a . (infinite {b . [(a,b)]\<bullet>x \<noteq> x})}"

fresh :: "'x \<Rightarrow> 'a \<Rightarrow> bool" ("_ \<sharp> _" [80,80] 80)
"a \<sharp> x \<equiv> a \<notin> supp x"

supports :: "'x set \<Rightarrow> 'a \<Rightarrow> bool" (infixl 80)
"S supports x \<equiv> \<forall>a b. (a\<notin>S \<and> b\<notin>S \<longrightarrow> [(a,b)]\<bullet>x=x)"

lemma supp_fresh_iff:
fixes x :: "'a"
shows "(supp x) = {a::'x. \<not>a\<sharp>x}"
done

lemma supp_unit:
shows "supp () = {}"

lemma supp_set_empty:
shows "supp {} = {}"
by (force simp add: supp_def perm_set_def)

lemma supp_singleton:
shows "supp {x} = supp x"
by (force simp add: supp_def perm_set_def)

lemma supp_prod:
fixes x :: "'a"
and   y :: "'b"
shows "(supp (x,y)) = (supp x)\<union>(supp y)"
by  (force simp add: supp_def Collect_imp_eq Collect_neg_eq)

lemma supp_nprod:
fixes x :: "'a"
and   y :: "'b"
shows "(supp (nPair x y)) = (supp x)\<union>(supp y)"
by  (force simp add: supp_def Collect_imp_eq Collect_neg_eq)

lemma supp_list_nil:
shows "supp [] = {}"
done

lemma supp_list_cons:
fixes x  :: "'a"
and   xs :: "'a list"
shows "supp (x#xs) = (supp x)\<union>(supp xs)"
apply(auto simp add: supp_def Collect_imp_eq Collect_neg_eq)
done

lemma supp_list_append:
fixes xs :: "'a list"
and   ys :: "'a list"
shows "supp (xs@ys) = (supp xs)\<union>(supp ys)"
by (induct xs, auto simp add: supp_list_nil supp_list_cons)

lemma supp_list_rev:
fixes xs :: "'a list"
shows "supp (rev xs) = (supp xs)"
by (induct xs, auto simp add: supp_list_append supp_list_cons supp_list_nil)

lemma supp_bool:
fixes x  :: "bool"
shows "supp (x) = {}"
apply(case_tac "x")
done

lemma supp_some:
fixes x :: "'a"
shows "supp (Some x) = (supp x)"
done

lemma supp_none:
fixes x :: "'a"
shows "supp (None) = {}"
done

lemma supp_int:
fixes i::"int"
shows "supp (i) = {}"
done

lemma supp_nat:
fixes n::"nat"
shows "supp (n) = {}"
done

lemma supp_char:
fixes c::"char"
shows "supp (c) = {}"
done

lemma supp_string:
fixes s::"string"
shows "supp (s) = {}"
apply(induct s)
apply(auto simp add: supp_char supp_list_nil supp_list_cons)
done

lemma fresh_set_empty:
shows "a\<sharp>{}"

lemma fresh_singleton:
shows "a\<sharp>{x} = a\<sharp>x"

lemma fresh_unit:
shows "a\<sharp>()"

lemma fresh_prod:
fixes a :: "'x"
and   x :: "'a"
and   y :: "'b"
shows "a\<sharp>(x,y) = (a\<sharp>x \<and> a\<sharp>y)"

lemma fresh_list_nil:
fixes a :: "'x"
shows "a\<sharp>[]"

lemma fresh_list_cons:
fixes a :: "'x"
and   x :: "'a"
and   xs :: "'a list"
shows "a\<sharp>(x#xs) = (a\<sharp>x \<and> a\<sharp>xs)"

lemma fresh_list_append:
fixes a :: "'x"
and   xs :: "'a list"
and   ys :: "'a list"
shows "a\<sharp>(xs@ys) = (a\<sharp>xs \<and> a\<sharp>ys)"

lemma fresh_list_rev:
fixes a :: "'x"
and   xs :: "'a list"
shows "a\<sharp>(rev xs) = a\<sharp>xs"

lemma fresh_none:
fixes a :: "'x"
shows "a\<sharp>None"
done

lemma fresh_some:
fixes a :: "'x"
and   x :: "'a"
shows "a\<sharp>(Some x) = a\<sharp>x"
done

lemma fresh_int:
fixes a :: "'x"
and   i :: "int"
shows "a\<sharp>i"
done

lemma fresh_nat:
fixes a :: "'x"
and   n :: "nat"
shows "a\<sharp>n"
done

lemma fresh_char:
fixes a :: "'x"
and   c :: "char"
shows "a\<sharp>c"
done

lemma fresh_string:
fixes a :: "'x"
and   s :: "string"
shows "a\<sharp>s"
done

text {* Normalization of freshness results; cf.\ @{text nominal_induct} *}

lemma fresh_unit_elim:
shows "(a\<sharp>() \<Longrightarrow> PROP C) \<equiv> PROP C"

lemma fresh_prod_elim:
shows "(a\<sharp>(x,y) \<Longrightarrow> PROP C) \<equiv> (a\<sharp>x \<Longrightarrow> a\<sharp>y \<Longrightarrow> PROP C)"

(* this rule needs to be added before the fresh_prodD is *)
(* added to the simplifier with mksimps                  *)
lemma [simp]:
shows "a\<sharp>x1 \<Longrightarrow> a\<sharp>x2 \<Longrightarrow> a\<sharp>(x1,x2)"

lemma fresh_prodD:
shows "a\<sharp>(x,y) \<Longrightarrow> a\<sharp>x"
and   "a\<sharp>(x,y) \<Longrightarrow> a\<sharp>y"

ML_setup {*
val mksimps_pairs = ("Nominal.fresh", thms "fresh_prodD")::mksimps_pairs;
change_simpset (fn ss => ss setmksimps (mksimps mksimps_pairs));
*}

section {* Abstract Properties for Permutations and  Atoms *}
(*=========================================================*)

(* properties for being a permutation type *)
constdefs
"pt TYPE('a) TYPE('x) \<equiv>
(\<forall>(x::'a). ([]::'x prm)\<bullet>x = x) \<and>
(\<forall>(pi1::'x prm) (pi2::'x prm) (x::'a). (pi1@pi2)\<bullet>x = pi1\<bullet>(pi2\<bullet>x)) \<and>
(\<forall>(pi1::'x prm) (pi2::'x prm) (x::'a). pi1 \<triangleq> pi2 \<longrightarrow> pi1\<bullet>x = pi2\<bullet>x)"

(* properties for being an atom type *)
constdefs
"at TYPE('x) \<equiv>
(\<forall>(x::'x). ([]::'x prm)\<bullet>x = x) \<and>
(\<forall>(a::'x) (b::'x) (pi::'x prm) (x::'x). ((a,b)#(pi::'x prm))\<bullet>x = swap (a,b) (pi\<bullet>x)) \<and>
(\<forall>(a::'x) (b::'x) (c::'x). swap (a,b) c = (if a=c then b else (if b=c then a else c))) \<and>
(infinite (UNIV::'x set))"

(* property of two atom-types being disjoint *)
constdefs
"disjoint TYPE('x) TYPE('y) \<equiv>
(\<forall>(pi::'x prm)(x::'y). pi\<bullet>x = x) \<and>
(\<forall>(pi::'y prm)(x::'x). pi\<bullet>x = x)"

(* composition property of two permutation on a type 'a *)
constdefs
"cp TYPE ('a) TYPE('x) TYPE('y) \<equiv>
(\<forall>(pi2::'y prm) (pi1::'x prm) (x::'a) . pi1\<bullet>(pi2\<bullet>x) = (pi1\<bullet>pi2)\<bullet>(pi1\<bullet>x))"

(* property of having finite support *)
constdefs
"fs TYPE('a) TYPE('x) \<equiv> \<forall>(x::'a). finite ((supp x)::'x set)"

section {* Lemmas about the atom-type properties*}
(*==============================================*)

lemma at1:
fixes x::"'x"
assumes a: "at TYPE('x)"
shows "([]::'x prm)\<bullet>x = x"
using a by (simp add: at_def)

lemma at2:
fixes a ::"'x"
and   b ::"'x"
and   x ::"'x"
and   pi::"'x prm"
assumes a: "at TYPE('x)"
shows "((a,b)#pi)\<bullet>x = swap (a,b) (pi\<bullet>x)"
using a by (simp only: at_def)

lemma at3:
fixes a ::"'x"
and   b ::"'x"
and   c ::"'x"
assumes a: "at TYPE('x)"
shows "swap (a,b) c = (if a=c then b else (if b=c then a else c))"
using a by (simp only: at_def)

(* rules to calculate simple premutations *)
lemmas at_calc = at2 at1 at3

lemma at_swap_simps:
fixes a ::"'x"
and   b ::"'x"
assumes a: "at TYPE('x)"
shows "[(a,b)]\<bullet>a = b"
and   "[(a,b)]\<bullet>b = a"
using a by (simp_all add: at_calc)

lemma at4:
assumes a: "at TYPE('x)"
shows "infinite (UNIV::'x set)"
using a by (simp add: at_def)

lemma at_append:
fixes pi1 :: "'x prm"
and   pi2 :: "'x prm"
and   c   :: "'x"
assumes at: "at TYPE('x)"
shows "(pi1@pi2)\<bullet>c = pi1\<bullet>(pi2\<bullet>c)"
proof (induct pi1)
case Nil show ?case by (simp add: at1[OF at])
next
case (Cons x xs)
have "(xs@pi2)\<bullet>c  =  xs\<bullet>(pi2\<bullet>c)" by fact
also have "(x#xs)@pi2 = x#(xs@pi2)" by simp
ultimately show ?case by (cases "x", simp add:  at2[OF at])
qed

lemma at_swap:
fixes a :: "'x"
and   b :: "'x"
and   c :: "'x"
assumes at: "at TYPE('x)"
shows "swap (a,b) (swap (a,b) c) = c"
by (auto simp add: at3[OF at])

lemma at_rev_pi:
fixes pi :: "'x prm"
and   c  :: "'x"
assumes at: "at TYPE('x)"
shows "(rev pi)\<bullet>(pi\<bullet>c) = c"
proof(induct pi)
case Nil show ?case by (simp add: at1[OF at])
next
case (Cons x xs) thus ?case
by (cases "x", simp add: at2[OF at] at_append[OF at] at1[OF at] at_swap[OF at])
qed

lemma at_pi_rev:
fixes pi :: "'x prm"
and   x  :: "'x"
assumes at: "at TYPE('x)"
shows "pi\<bullet>((rev pi)\<bullet>x) = x"
by (rule at_rev_pi[OF at, of "rev pi" _,simplified])

lemma at_bij1:
fixes pi :: "'x prm"
and   x  :: "'x"
and   y  :: "'x"
assumes at: "at TYPE('x)"
and     a:  "(pi\<bullet>x) = y"
shows   "x=(rev pi)\<bullet>y"
proof -
from a have "y=(pi\<bullet>x)" by (rule sym)
thus ?thesis by (simp only: at_rev_pi[OF at])
qed

lemma at_bij2:
fixes pi :: "'x prm"
and   x  :: "'x"
and   y  :: "'x"
assumes at: "at TYPE('x)"
and     a:  "((rev pi)\<bullet>x) = y"
shows   "x=pi\<bullet>y"
proof -
from a have "y=((rev pi)\<bullet>x)" by (rule sym)
thus ?thesis by (simp only: at_pi_rev[OF at])
qed

lemma at_bij:
fixes pi :: "'x prm"
and   x  :: "'x"
and   y  :: "'x"
assumes at: "at TYPE('x)"
shows "(pi\<bullet>x = pi\<bullet>y) = (x=y)"
proof
assume "pi\<bullet>x = pi\<bullet>y"
hence  "x=(rev pi)\<bullet>(pi\<bullet>y)" by (rule at_bij1[OF at])
thus "x=y" by (simp only: at_rev_pi[OF at])
next
assume "x=y"
thus "pi\<bullet>x = pi\<bullet>y" by simp
qed

lemma at_supp:
fixes x :: "'x"
assumes at: "at TYPE('x)"
shows "supp x = {x}"
proof (simp add: supp_def Collect_conj_eq Collect_imp_eq at_calc[OF at], auto)
assume f: "finite {b::'x. b \<noteq> x}"
have a1: "{b::'x. b \<noteq> x} = UNIV-{x}" by force
have a2: "infinite (UNIV::'x set)" by (rule at4[OF at])
from f a1 a2 show False by force
qed

lemma at_fresh:
fixes a :: "'x"
and   b :: "'x"
assumes at: "at TYPE('x)"
shows "(a\<sharp>b) = (a\<noteq>b)"
by (simp add: at_supp[OF at] fresh_def)

lemma at_prm_fresh:
fixes c :: "'x"
and   pi:: "'x prm"
assumes at: "at TYPE('x)"
and     a: "c\<sharp>pi"
shows "pi\<bullet>c = c"
using a
apply(induct pi)
apply(force simp add: fresh_list_cons at2[OF at] fresh_prod at_fresh[OF at] at3[OF at])
done

lemma at_prm_rev_eq:
fixes pi1 :: "'x prm"
and   pi2 :: "'x prm"
assumes at: "at TYPE('x)"
shows "((rev pi1) \<triangleq> (rev pi2)) = (pi1 \<triangleq> pi2)"
fix x
assume "\<forall>x::'x. (rev pi1)\<bullet>x = (rev pi2)\<bullet>x"
hence "(rev (pi1::'x prm))\<bullet>(pi2\<bullet>(x::'x)) = (rev (pi2::'x prm))\<bullet>(pi2\<bullet>x)" by simp
hence "(rev (pi1::'x prm))\<bullet>((pi2::'x prm)\<bullet>x) = (x::'x)" by (simp add: at_rev_pi[OF at])
hence "(pi2::'x prm)\<bullet>x = (pi1::'x prm)\<bullet>x" by (simp add: at_bij2[OF at])
thus "pi1\<bullet>x  =  pi2\<bullet>x" by simp
next
fix x
assume "\<forall>x::'x. pi1\<bullet>x = pi2\<bullet>x"
hence "(pi1::'x prm)\<bullet>((rev pi2)\<bullet>x) = (pi2::'x prm)\<bullet>((rev pi2)\<bullet>(x::'x))" by simp
hence "(pi1::'x prm)\<bullet>((rev pi2)\<bullet>(x::'x)) = x" by (simp add: at_pi_rev[OF at])
hence "(rev pi2)\<bullet>x = (rev pi1)\<bullet>(x::'x)" by (simp add: at_bij1[OF at])
thus "(rev pi1)\<bullet>x = (rev pi2)\<bullet>(x::'x)" by simp
qed

lemma at_prm_eq_append:
fixes pi1 :: "'x prm"
and   pi2 :: "'x prm"
and   pi3 :: "'x prm"
assumes at: "at TYPE('x)"
and     a: "pi1 \<triangleq> pi2"
shows "(pi3@pi1) \<triangleq> (pi3@pi2)"
using a by (simp add: prm_eq_def at_append[OF at] at_bij[OF at])

lemma at_prm_eq_append':
fixes pi1 :: "'x prm"
and   pi2 :: "'x prm"
and   pi3 :: "'x prm"
assumes at: "at TYPE('x)"
and     a: "pi1 \<triangleq> pi2"
shows "(pi1@pi3) \<triangleq> (pi2@pi3)"
using a by (simp add: prm_eq_def at_append[OF at])

lemma at_prm_eq_trans:
fixes pi1 :: "'x prm"
and   pi2 :: "'x prm"
and   pi3 :: "'x prm"
assumes a1: "pi1 \<triangleq> pi2"
and     a2: "pi2 \<triangleq> pi3"
shows "pi1 \<triangleq> pi3"
using a1 a2 by (auto simp add: prm_eq_def)

lemma at_prm_eq_refl:
fixes pi :: "'x prm"
shows "pi \<triangleq> pi"

lemma at_prm_rev_eq1:
fixes pi1 :: "'x prm"
and   pi2 :: "'x prm"
assumes at: "at TYPE('x)"
shows "pi1 \<triangleq> pi2 \<Longrightarrow> (rev pi1) \<triangleq> (rev pi2)"

lemma at_ds1:
fixes a  :: "'x"
assumes at: "at TYPE('x)"
shows "[(a,a)] \<triangleq> []"
by (force simp add: prm_eq_def at_calc[OF at])

lemma at_ds2:
fixes pi :: "'x prm"
and   a  :: "'x"
and   b  :: "'x"
assumes at: "at TYPE('x)"
shows "([(a,b)]@pi) \<triangleq> (pi@[((rev pi)\<bullet>a,(rev pi)\<bullet>b)])"
by (force simp add: prm_eq_def at_append[OF at] at_bij[OF at] at_pi_rev[OF at]
at_rev_pi[OF at] at_calc[OF at])

lemma at_ds3:
fixes a  :: "'x"
and   b  :: "'x"
and   c  :: "'x"
assumes at: "at TYPE('x)"
and     a:  "distinct [a,b,c]"
shows "[(a,c),(b,c),(a,c)] \<triangleq> [(a,b)]"
using a by (force simp add: prm_eq_def at_calc[OF at])

lemma at_ds4:
fixes a  :: "'x"
and   b  :: "'x"
and   pi  :: "'x prm"
assumes at: "at TYPE('x)"
shows "(pi@[(a,(rev pi)\<bullet>b)]) \<triangleq> ([(pi\<bullet>a,b)]@pi)"
by (force simp add: prm_eq_def at_append[OF at] at_calc[OF at] at_bij[OF at]
at_pi_rev[OF at] at_rev_pi[OF at])

lemma at_ds5:
fixes a  :: "'x"
and   b  :: "'x"
assumes at: "at TYPE('x)"
shows "[(a,b)] \<triangleq> [(b,a)]"
by (force simp add: prm_eq_def at_calc[OF at])

lemma at_ds5':
fixes a  :: "'x"
and   b  :: "'x"
assumes at: "at TYPE('x)"
shows "[(a,b),(b,a)] \<triangleq> []"
by (force simp add: prm_eq_def at_calc[OF at])

lemma at_ds6:
fixes a  :: "'x"
and   b  :: "'x"
and   c  :: "'x"
assumes at: "at TYPE('x)"
and     a: "distinct [a,b,c]"
shows "[(a,c),(a,b)] \<triangleq> [(b,c),(a,c)]"
using a by (force simp add: prm_eq_def at_calc[OF at])

lemma at_ds7:
fixes pi :: "'x prm"
assumes at: "at TYPE('x)"
shows "((rev pi)@pi) \<triangleq> []"
by (simp add: prm_eq_def at1[OF at] at_append[OF at] at_rev_pi[OF at])

lemma at_ds8_aux:
fixes pi :: "'x prm"
and   a  :: "'x"
and   b  :: "'x"
and   c  :: "'x"
assumes at: "at TYPE('x)"
shows "pi\<bullet>(swap (a,b) c) = swap (pi\<bullet>a,pi\<bullet>b) (pi\<bullet>c)"
by (force simp add: at_calc[OF at] at_bij[OF at])

lemma at_ds8:
fixes pi1 :: "'x prm"
and   pi2 :: "'x prm"
and   a  :: "'x"
and   b  :: "'x"
assumes at: "at TYPE('x)"
shows "(pi1@pi2) \<triangleq> ((pi1\<bullet>pi2)@pi1)"
apply(induct_tac pi2)
apply(drule_tac x="aa" in spec)
apply(drule sym)
apply(simp)
done

lemma at_ds9:
fixes pi1 :: "'x prm"
and   pi2 :: "'x prm"
and   a  :: "'x"
and   b  :: "'x"
assumes at: "at TYPE('x)"
shows " ((rev pi2)@(rev pi1)) \<triangleq> ((rev pi1)@(rev (pi1\<bullet>pi2)))"
apply(induct_tac pi2)
apply(simp add: at2[OF at] at1[OF at])
apply(drule_tac x="swap(pi1\<bullet>a,pi1\<bullet>b) aa" in spec)
apply(drule sym)
apply(simp)
done

lemma at_ds10:
fixes pi :: "'x prm"
and   a  :: "'x"
and   b  :: "'x"
assumes at: "at TYPE('x)"
and     a:  "b\<sharp>(rev pi)"
shows "([(pi\<bullet>a,b)]@pi) \<triangleq> (pi@[(a,b)])"
using a
apply -
apply(rule at_prm_eq_trans)
apply(rule at_ds2[OF at])
apply(simp add: at_prm_fresh[OF at] at_rev_pi[OF at])
apply(rule at_prm_eq_refl)
done

--"there always exists an atom that is not being in a finite set"
lemma ex_in_inf:
fixes   A::"'x set"
assumes at: "at TYPE('x)"
and     fs: "finite A"
obtains c::"'x" where "c\<notin>A"
proof -
from  fs at4[OF at] have "infinite ((UNIV::'x set) - A)"
hence "((UNIV::'x set) - A) \<noteq> ({}::'x set)" by (force simp only:)
then obtain c::"'x" where "c\<in>((UNIV::'x set) - A)" by force
then have "c\<notin>A" by simp
then show ?thesis using prems by simp
qed

text {* there always exists a fresh name for an object with finite support *}
lemma at_exists_fresh':
fixes  x :: "'a"
assumes at: "at TYPE('x)"
and     fs: "finite ((supp x)::'x set)"
shows "\<exists>c::'x. c\<sharp>x"
by (auto simp add: fresh_def intro: ex_in_inf[OF at, OF fs])

lemma at_exists_fresh:
fixes  x :: "'a"
assumes at: "at TYPE('x)"
and     fs: "finite ((supp x)::'x set)"
obtains c::"'x" where  "c\<sharp>x"
by (auto intro: ex_in_inf[OF at, OF fs] simp add: fresh_def)

lemma at_finite_select:
shows "at (TYPE('a)) \<Longrightarrow> finite (S::'a set) \<Longrightarrow> \<exists>x. x \<notin> S"
apply (drule Diff_infinite_finite)
apply blast
apply (subgoal_tac "UNIV - S \<noteq> {}")
apply (simp only: ex_in_conv [symmetric])
apply blast
apply (rule notI)
apply simp
done

lemma at_different:
assumes at: "at TYPE('x)"
shows "\<exists>(b::'x). a\<noteq>b"
proof -
have "infinite (UNIV::'x set)" by (rule at4[OF at])
hence inf2: "infinite (UNIV-{a})" by (rule infinite_remove)
have "(UNIV-{a}) \<noteq> ({}::'x set)"
proof (rule_tac ccontr, drule_tac notnotD)
assume "UNIV-{a} = ({}::'x set)"
with inf2 have "infinite ({}::'x set)" by simp
then show "False" by auto
qed
hence "\<exists>(b::'x). b\<in>(UNIV-{a})" by blast
then obtain b::"'x" where mem2: "b\<in>(UNIV-{a})" by blast
from mem2 have "a\<noteq>b" by blast
then show "\<exists>(b::'x). a\<noteq>b" by blast
qed

--"the at-props imply the pt-props"
lemma at_pt_inst:
assumes at: "at TYPE('x)"
shows "pt TYPE('x) TYPE('x)"
apply(auto simp only: pt_def)
apply(simp only: at1[OF at])
apply(simp only: at_append[OF at])
apply(simp only: prm_eq_def)
done

section {* finite support properties *}
(*===================================*)

lemma fs1:
fixes x :: "'a"
assumes a: "fs TYPE('a) TYPE('x)"
shows "finite ((supp x)::'x set)"
using a by (simp add: fs_def)

lemma fs_at_inst:
fixes a :: "'x"
assumes at: "at TYPE('x)"
shows "fs TYPE('x) TYPE('x)"
done

lemma fs_unit_inst:
shows "fs TYPE(unit) TYPE('x)"
done

lemma fs_prod_inst:
assumes fsa: "fs TYPE('a) TYPE('x)"
and     fsb: "fs TYPE('b) TYPE('x)"
shows "fs TYPE('a\<times>'b) TYPE('x)"
apply(unfold fs_def)
apply(rule fs1[OF fsa])
apply(rule fs1[OF fsb])
done

lemma fs_nprod_inst:
assumes fsa: "fs TYPE('a) TYPE('x)"
and     fsb: "fs TYPE('b) TYPE('x)"
shows "fs TYPE(('a,'b) nprod) TYPE('x)"
apply(unfold fs_def, rule allI)
apply(case_tac x)
apply(rule fs1[OF fsa])
apply(rule fs1[OF fsb])
done

lemma fs_list_inst:
assumes fs: "fs TYPE('a) TYPE('x)"
shows "fs TYPE('a list) TYPE('x)"
apply(induct_tac x)
apply(rule fs1[OF fs])
done

lemma fs_option_inst:
assumes fs: "fs TYPE('a) TYPE('x)"
shows "fs TYPE('a option) TYPE('x)"
apply(case_tac x)
apply(rule fs1[OF fs])
done

section {* Lemmas about the permutation properties *}
(*=================================================*)

lemma pt1:
fixes x::"'a"
assumes a: "pt TYPE('a) TYPE('x)"
shows "([]::'x prm)\<bullet>x = x"
using a by (simp add: pt_def)

lemma pt2:
fixes pi1::"'x prm"
and   pi2::"'x prm"
and   x  ::"'a"
assumes a: "pt TYPE('a) TYPE('x)"
shows "(pi1@pi2)\<bullet>x = pi1\<bullet>(pi2\<bullet>x)"
using a by (simp add: pt_def)

lemma pt3:
fixes pi1::"'x prm"
and   pi2::"'x prm"
and   x  ::"'a"
assumes a: "pt TYPE('a) TYPE('x)"
shows "pi1 \<triangleq> pi2 \<Longrightarrow> pi1\<bullet>x = pi2\<bullet>x"
using a by (simp add: pt_def)

lemma pt3_rev:
fixes pi1::"'x prm"
and   pi2::"'x prm"
and   x  ::"'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "pi1 \<triangleq> pi2 \<Longrightarrow> (rev pi1)\<bullet>x = (rev pi2)\<bullet>x"
by (rule pt3[OF pt], simp add: at_prm_rev_eq[OF at])

section {* composition properties *}
(* ============================== *)
lemma cp1:
fixes pi1::"'x prm"
and   pi2::"'y prm"
and   x  ::"'a"
assumes cp: "cp TYPE ('a) TYPE('x) TYPE('y)"
shows "pi1\<bullet>(pi2\<bullet>x) = (pi1\<bullet>pi2)\<bullet>(pi1\<bullet>x)"
using cp by (simp add: cp_def)

lemma cp_pt_inst:
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "cp TYPE('a) TYPE('x) TYPE('x)"
apply(auto simp add: cp_def pt2[OF pt,symmetric])
apply(rule pt3[OF pt])
apply(rule at_ds8[OF at])
done

section {* disjointness properties *}
(*=================================*)
lemma dj_perm_forget:
fixes pi::"'y prm"
and   x ::"'x"
assumes dj: "disjoint TYPE('x) TYPE('y)"
shows "pi\<bullet>x=x"
using dj by (simp_all add: disjoint_def)

lemma dj_perm_perm_forget:
fixes pi1::"'x prm"
and   pi2::"'y prm"
assumes dj: "disjoint TYPE('x) TYPE('y)"
shows "pi2\<bullet>pi1=pi1"
using dj by (induct pi1, auto simp add: disjoint_def)

lemma dj_cp:
fixes pi1::"'x prm"
and   pi2::"'y prm"
and   x  ::"'a"
assumes cp: "cp TYPE ('a) TYPE('x) TYPE('y)"
and     dj: "disjoint TYPE('y) TYPE('x)"
shows "pi1\<bullet>(pi2\<bullet>x) = (pi2)\<bullet>(pi1\<bullet>x)"
by (simp add: cp1[OF cp] dj_perm_perm_forget[OF dj])

lemma dj_supp:
fixes a::"'x"
assumes dj: "disjoint TYPE('x) TYPE('y)"
shows "(supp a) = ({}::'y set)"
done

lemma at_fresh_ineq:
fixes a :: "'x"
and   b :: "'y"
assumes dj: "disjoint TYPE('y) TYPE('x)"
shows "a\<sharp>b"
by (simp add: fresh_def dj_supp[OF dj])

section {* permutation type instances *}
(* ===================================*)

lemma pt_set_inst:
assumes pt: "pt TYPE('a) TYPE('x)"
shows  "pt TYPE('a set) TYPE('x)"
apply(force simp add: pt2[OF pt] pt3[OF pt])
done

lemma pt_list_nil:
fixes xs :: "'a list"
assumes pt: "pt TYPE('a) TYPE ('x)"
shows "([]::'x prm)\<bullet>xs = xs"
apply(induct_tac xs)
done

lemma pt_list_append:
fixes pi1 :: "'x prm"
and   pi2 :: "'x prm"
and   xs  :: "'a list"
assumes pt: "pt TYPE('a) TYPE ('x)"
shows "(pi1@pi2)\<bullet>xs = pi1\<bullet>(pi2\<bullet>xs)"
apply(induct_tac xs)
done

lemma pt_list_prm_eq:
fixes pi1 :: "'x prm"
and   pi2 :: "'x prm"
and   xs  :: "'a list"
assumes pt: "pt TYPE('a) TYPE ('x)"
shows "pi1 \<triangleq> pi2  \<Longrightarrow> pi1\<bullet>xs = pi2\<bullet>xs"
apply(induct_tac xs)
done

lemma pt_list_inst:
assumes pt: "pt TYPE('a) TYPE('x)"
shows  "pt TYPE('a list) TYPE('x)"
apply(auto simp only: pt_def)
apply(rule pt_list_nil[OF pt])
apply(rule pt_list_append[OF pt])
apply(rule pt_list_prm_eq[OF pt],assumption)
done

lemma pt_unit_inst:
shows  "pt TYPE(unit) TYPE('x)"

lemma pt_prod_inst:
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('b) TYPE('x)"
shows  "pt TYPE('a \<times> 'b) TYPE('x)"
apply(rule pt1[OF pta])
apply(rule pt1[OF ptb])
apply(rule pt2[OF pta])
apply(rule pt2[OF ptb])
apply(rule pt3[OF pta],assumption)
apply(rule pt3[OF ptb],assumption)
done

lemma pt_nprod_inst:
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('b) TYPE('x)"
shows  "pt TYPE(('a,'b) nprod) TYPE('x)"
apply(case_tac x)
apply(simp add: pt1[OF pta] pt1[OF ptb])
apply(case_tac x)
apply(simp add: pt2[OF pta] pt2[OF ptb])
apply(case_tac x)
apply(simp add: pt3[OF pta] pt3[OF ptb])
done

lemma pt_fun_inst:
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('b) TYPE('x)"
and     at:  "at TYPE('x)"
shows  "pt TYPE('a\<Rightarrow>'b) TYPE('x)"
apply(auto simp only: pt_def)
apply(simp add: pt1[OF pta] pt1[OF ptb])
apply(simp add: pt2[OF pta] pt2[OF ptb])
apply(subgoal_tac "(rev pi1) \<triangleq> (rev pi2)")(*A*)
apply(simp add: pt3[OF pta] pt3[OF ptb])
(*A*)
done

lemma pt_option_inst:
assumes pta: "pt TYPE('a) TYPE('x)"
shows  "pt TYPE('a option) TYPE('x)"
apply(auto simp only: pt_def)
apply(case_tac "x")
apply(case_tac "x")
apply(case_tac "x")
done

lemma pt_noption_inst:
assumes pta: "pt TYPE('a) TYPE('x)"
shows  "pt TYPE('a noption) TYPE('x)"
apply(auto simp only: pt_def)
apply(case_tac "x")
apply(case_tac "x")
apply(case_tac "x")
done

section {* further lemmas for permutation types *}
(*==============================================*)

lemma pt_rev_pi:
fixes pi :: "'x prm"
and   x  :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "(rev pi)\<bullet>(pi\<bullet>x) = x"
proof -
have "((rev pi)@pi) \<triangleq> ([]::'x prm)" by (simp add: at_ds7[OF at])
hence "((rev pi)@pi)\<bullet>(x::'a) = ([]::'x prm)\<bullet>x" by (simp add: pt3[OF pt])
thus ?thesis by (simp add: pt1[OF pt] pt2[OF pt])
qed

lemma pt_pi_rev:
fixes pi :: "'x prm"
and   x  :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "pi\<bullet>((rev pi)\<bullet>x) = x"
by (simp add: pt_rev_pi[OF pt, OF at,of "rev pi" "x",simplified])

lemma pt_bij1:
fixes pi :: "'x prm"
and   x  :: "'a"
and   y  :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     a:  "(pi\<bullet>x) = y"
shows   "x=(rev pi)\<bullet>y"
proof -
from a have "y=(pi\<bullet>x)" by (rule sym)
thus ?thesis by (simp only: pt_rev_pi[OF pt, OF at])
qed

lemma pt_bij2:
fixes pi :: "'x prm"
and   x  :: "'a"
and   y  :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     a:  "x = (rev pi)\<bullet>y"
shows   "(pi\<bullet>x)=y"
using a by (simp add: pt_pi_rev[OF pt, OF at])

lemma pt_bij:
fixes pi :: "'x prm"
and   x  :: "'a"
and   y  :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "(pi\<bullet>x = pi\<bullet>y) = (x=y)"
proof
assume "pi\<bullet>x = pi\<bullet>y"
hence  "x=(rev pi)\<bullet>(pi\<bullet>y)" by (rule pt_bij1[OF pt, OF at])
thus "x=y" by (simp only: pt_rev_pi[OF pt, OF at])
next
assume "x=y"
thus "pi\<bullet>x = pi\<bullet>y" by simp
qed

lemma pt_eq_eqvt:
fixes pi :: "'x prm"
and   x  :: "'a"
and   y  :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "pi \<bullet> (x=y) = (pi\<bullet>x = pi\<bullet>y)"
using assms
by (auto simp add: pt_bij perm_bool)

lemma pt_bij3:
fixes pi :: "'x prm"
and   x  :: "'a"
and   y  :: "'a"
assumes a:  "x=y"
shows "(pi\<bullet>x = pi\<bullet>y)"
using a by simp

lemma pt_bij4:
fixes pi :: "'x prm"
and   x  :: "'a"
and   y  :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     a:  "pi\<bullet>x = pi\<bullet>y"
shows "x = y"
using a by (simp add: pt_bij[OF pt, OF at])

lemma pt_swap_bij:
fixes a  :: "'x"
and   b  :: "'x"
and   x  :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "[(a,b)]\<bullet>([(a,b)]\<bullet>x) = x"
by (rule pt_bij2[OF pt, OF at], simp)

lemma pt_swap_bij':
fixes a  :: "'x"
and   b  :: "'x"
and   x  :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "[(a,b)]\<bullet>([(b,a)]\<bullet>x) = x"
apply(rule trans)
apply(rule pt3[OF pt])
apply(rule at_ds5'[OF at])
apply(rule pt1[OF pt])
done

lemma pt_set_bij1:
fixes pi :: "'x prm"
and   x  :: "'a"
and   X  :: "'a set"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "((pi\<bullet>x)\<in>X) = (x\<in>((rev pi)\<bullet>X))"
by (force simp add: perm_set_def pt_rev_pi[OF pt, OF at] pt_pi_rev[OF pt, OF at])

lemma pt_set_bij1a:
fixes pi :: "'x prm"
and   x  :: "'a"
and   X  :: "'a set"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "(x\<in>(pi\<bullet>X)) = (((rev pi)\<bullet>x)\<in>X)"
by (force simp add: perm_set_def pt_rev_pi[OF pt, OF at] pt_pi_rev[OF pt, OF at])

lemma pt_set_bij:
fixes pi :: "'x prm"
and   x  :: "'a"
and   X  :: "'a set"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "((pi\<bullet>x)\<in>(pi\<bullet>X)) = (x\<in>X)"
by (simp add: perm_set_def pt_bij[OF pt, OF at])

lemma pt_in_eqvt:
fixes pi :: "'x prm"
and   x  :: "'a"
and   X  :: "'a set"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "pi\<bullet>(x\<in>X)=((pi\<bullet>x)\<in>(pi\<bullet>X))"
using assms
by (auto simp add:  pt_set_bij perm_bool)

lemma pt_set_bij2:
fixes pi :: "'x prm"
and   x  :: "'a"
and   X  :: "'a set"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     a:  "x\<in>X"
shows "(pi\<bullet>x)\<in>(pi\<bullet>X)"
using a by (simp add: pt_set_bij[OF pt, OF at])

lemma pt_set_bij2a:
fixes pi :: "'x prm"
and   x  :: "'a"
and   X  :: "'a set"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     a:  "x\<in>((rev pi)\<bullet>X)"
shows "(pi\<bullet>x)\<in>X"
using a by (simp add: pt_set_bij1[OF pt, OF at])

lemma pt_set_bij3:
fixes pi :: "'x prm"
and   x  :: "'a"
and   X  :: "'a set"
shows "pi\<bullet>(x\<in>X) = (x\<in>X)"
apply(case_tac "x\<in>X = True")
apply(auto)
done

lemma pt_subseteq_eqvt:
fixes pi :: "'x prm"
and   Y  :: "'a set"
and   X  :: "'a set"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "((pi\<bullet>X)\<subseteq>(pi\<bullet>Y)) = (X\<subseteq>Y)"
proof (auto)
fix x::"'a"
assume a: "(pi\<bullet>X)\<subseteq>(pi\<bullet>Y)"
and    "x\<in>X"
hence  "(pi\<bullet>x)\<in>(pi\<bullet>X)" by (simp add: pt_set_bij[OF pt, OF at])
with a have "(pi\<bullet>x)\<in>(pi\<bullet>Y)" by force
thus "x\<in>Y" by (simp add: pt_set_bij[OF pt, OF at])
next
fix x::"'a"
assume a: "X\<subseteq>Y"
and    "x\<in>(pi\<bullet>X)"
thus "x\<in>(pi\<bullet>Y)" by (force simp add: pt_set_bij1a[OF pt, OF at])
qed

lemma pt_set_diff_eqvt:
fixes X::"'a set"
and   Y::"'a set"
and   pi::"'x prm"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "pi \<bullet> (X - Y) = (pi \<bullet> X) - (pi \<bullet> Y)"
by (auto simp add: perm_set_def pt_bij[OF pt, OF at])

-- "some helper lemmas for the pt_perm_supp_ineq lemma"
lemma Collect_permI:
fixes pi :: "'x prm"
and   x  :: "'a"
assumes a: "\<forall>x. (P1 x = P2 x)"
shows "{pi\<bullet>x| x. P1 x} = {pi\<bullet>x| x. P2 x}"
using a by force

lemma Infinite_cong:
assumes a: "X = Y"
shows "infinite X = infinite Y"
using a by (simp)

lemma pt_set_eq_ineq:
fixes pi :: "'y prm"
assumes pt: "pt TYPE('x) TYPE('y)"
and     at: "at TYPE('y)"
shows "{pi\<bullet>x| x::'x. P x} = {x::'x. P ((rev pi)\<bullet>x)}"
by (force simp only: pt_rev_pi[OF pt, OF at] pt_pi_rev[OF pt, OF at])

lemma pt_inject_on_ineq:
fixes X  :: "'y set"
and   pi :: "'x prm"
assumes pt: "pt TYPE('y) TYPE('x)"
and     at: "at TYPE('x)"
shows "inj_on (perm pi) X"
proof (unfold inj_on_def, intro strip)
fix x::"'y" and y::"'y"
assume "pi\<bullet>x = pi\<bullet>y"
thus "x=y" by (simp add: pt_bij[OF pt, OF at])
qed

lemma pt_set_finite_ineq:
fixes X  :: "'x set"
and   pi :: "'y prm"
assumes pt: "pt TYPE('x) TYPE('y)"
and     at: "at TYPE('y)"
shows "finite (pi\<bullet>X) = finite X"
proof -
have image: "(pi\<bullet>X) = (perm pi ` X)" by (force simp only: perm_set_def)
show ?thesis
proof (rule iffI)
assume "finite (pi\<bullet>X)"
hence "finite (perm pi ` X)" using image by (simp)
thus "finite X" using pt_inject_on_ineq[OF pt, OF at] by (rule finite_imageD)
next
assume "finite X"
hence "finite (perm pi ` X)" by (rule finite_imageI)
thus "finite (pi\<bullet>X)" using image by (simp)
qed
qed

lemma pt_set_infinite_ineq:
fixes X  :: "'x set"
and   pi :: "'y prm"
assumes pt: "pt TYPE('x) TYPE('y)"
and     at: "at TYPE('y)"
shows "infinite (pi\<bullet>X) = infinite X"
using pt at by (simp add: pt_set_finite_ineq)

lemma pt_perm_supp_ineq:
fixes  pi  :: "'x prm"
and    x   :: "'a"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('y) TYPE('x)"
and     at:  "at TYPE('x)"
and     cp:  "cp TYPE('a) TYPE('x) TYPE('y)"
shows "(pi\<bullet>((supp x)::'y set)) = supp (pi\<bullet>x)" (is "?LHS = ?RHS")
proof -
have "?LHS = {pi\<bullet>a | a. infinite {b. [(a,b)]\<bullet>x \<noteq> x}}" by (simp add: supp_def perm_set_def)
also have "\<dots> = {pi\<bullet>a | a. infinite {pi\<bullet>b | b. [(a,b)]\<bullet>x \<noteq> x}}"
proof (rule Collect_permI, rule allI, rule iffI)
fix a
assume "infinite {b::'y. [(a,b)]\<bullet>x  \<noteq> x}"
hence "infinite (pi\<bullet>{b::'y. [(a,b)]\<bullet>x \<noteq> x})" by (simp add: pt_set_infinite_ineq[OF ptb, OF at])
thus "infinite {pi\<bullet>b |b::'y. [(a,b)]\<bullet>x  \<noteq> x}" by (simp add: perm_set_def)
next
fix a
assume "infinite {pi\<bullet>b |b::'y. [(a,b)]\<bullet>x \<noteq> x}"
hence "infinite (pi\<bullet>{b::'y. [(a,b)]\<bullet>x \<noteq> x})" by (simp add: perm_set_def)
thus "infinite {b::'y. [(a,b)]\<bullet>x  \<noteq> x}"
by (simp add: pt_set_infinite_ineq[OF ptb, OF at])
qed
also have "\<dots> = {a. infinite {b::'y. [((rev pi)\<bullet>a,(rev pi)\<bullet>b)]\<bullet>x \<noteq> x}}"
by (simp add: pt_set_eq_ineq[OF ptb, OF at])
also have "\<dots> = {a. infinite {b. pi\<bullet>([((rev pi)\<bullet>a,(rev pi)\<bullet>b)]\<bullet>x) \<noteq> (pi\<bullet>x)}}"
by (simp add: pt_bij[OF pta, OF at])
also have "\<dots> = {a. infinite {b. [(a,b)]\<bullet>(pi\<bullet>x) \<noteq> (pi\<bullet>x)}}"
proof (rule Collect_cong, rule Infinite_cong, rule Collect_cong)
fix a::"'y" and b::"'y"
have "pi\<bullet>(([((rev pi)\<bullet>a,(rev pi)\<bullet>b)])\<bullet>x) = [(a,b)]\<bullet>(pi\<bullet>x)"
by (simp add: cp1[OF cp] pt_pi_rev[OF ptb, OF at])
thus "(pi\<bullet>([((rev pi)\<bullet>a,(rev pi)\<bullet>b)]\<bullet>x) \<noteq>  pi\<bullet>x) = ([(a,b)]\<bullet>(pi\<bullet>x) \<noteq> pi\<bullet>x)" by simp
qed
finally show "?LHS = ?RHS" by (simp add: supp_def)
qed

lemma pt_perm_supp:
fixes  pi  :: "'x prm"
and    x   :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "(pi\<bullet>((supp x)::'x set)) = supp (pi\<bullet>x)"
apply(rule pt_perm_supp_ineq)
apply(rule pt)
apply(rule at_pt_inst)
apply(rule at)+
apply(rule cp_pt_inst)
apply(rule pt)
apply(rule at)
done

lemma pt_supp_finite_pi:
fixes  pi  :: "'x prm"
and    x   :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     f: "finite ((supp x)::'x set)"
shows "finite ((supp (pi\<bullet>x))::'x set)"
apply(simp add: pt_perm_supp[OF pt, OF at, symmetric])
apply(simp add: pt_set_finite_ineq[OF at_pt_inst[OF at], OF at])
apply(rule f)
done

lemma pt_fresh_left_ineq:
fixes  pi :: "'x prm"
and     x :: "'a"
and     a :: "'y"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('y) TYPE('x)"
and     at:  "at TYPE('x)"
and     cp:  "cp TYPE('a) TYPE('x) TYPE('y)"
shows "a\<sharp>(pi\<bullet>x) = ((rev pi)\<bullet>a)\<sharp>x"
apply(simp add: pt_set_bij1[OF ptb, OF at])
apply(simp add: pt_perm_supp_ineq[OF pta, OF ptb, OF at, OF cp])
done

lemma pt_fresh_right_ineq:
fixes  pi :: "'x prm"
and     x :: "'a"
and     a :: "'y"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('y) TYPE('x)"
and     at:  "at TYPE('x)"
and     cp:  "cp TYPE('a) TYPE('x) TYPE('y)"
shows "(pi\<bullet>a)\<sharp>x = a\<sharp>((rev pi)\<bullet>x)"
apply(simp add: pt_set_bij1[OF ptb, OF at])
apply(simp add: pt_perm_supp_ineq[OF pta, OF ptb, OF at, OF cp])
done

lemma pt_fresh_bij_ineq:
fixes  pi :: "'x prm"
and     x :: "'a"
and     a :: "'y"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('y) TYPE('x)"
and     at:  "at TYPE('x)"
and     cp:  "cp TYPE('a) TYPE('x) TYPE('y)"
shows "(pi\<bullet>a)\<sharp>(pi\<bullet>x) = a\<sharp>x"
apply(simp add: pt_fresh_left_ineq[OF pta, OF ptb, OF at, OF cp])
apply(simp add: pt_rev_pi[OF ptb, OF at])
done

lemma pt_fresh_left:
fixes  pi :: "'x prm"
and     x :: "'a"
and     a :: "'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "a\<sharp>(pi\<bullet>x) = ((rev pi)\<bullet>a)\<sharp>x"
apply(rule pt_fresh_left_ineq)
apply(rule pt)
apply(rule at_pt_inst)
apply(rule at)+
apply(rule cp_pt_inst)
apply(rule pt)
apply(rule at)
done

lemma pt_fresh_right:
fixes  pi :: "'x prm"
and     x :: "'a"
and     a :: "'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "(pi\<bullet>a)\<sharp>x = a\<sharp>((rev pi)\<bullet>x)"
apply(rule pt_fresh_right_ineq)
apply(rule pt)
apply(rule at_pt_inst)
apply(rule at)+
apply(rule cp_pt_inst)
apply(rule pt)
apply(rule at)
done

lemma pt_fresh_bij:
fixes  pi :: "'x prm"
and     x :: "'a"
and     a :: "'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "(pi\<bullet>a)\<sharp>(pi\<bullet>x) = a\<sharp>x"
apply(rule pt_fresh_bij_ineq)
apply(rule pt)
apply(rule at_pt_inst)
apply(rule at)+
apply(rule cp_pt_inst)
apply(rule pt)
apply(rule at)
done

lemma pt_fresh_bij1:
fixes  pi :: "'x prm"
and     x :: "'a"
and     a :: "'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     a:  "a\<sharp>x"
shows "(pi\<bullet>a)\<sharp>(pi\<bullet>x)"
using a by (simp add: pt_fresh_bij[OF pt, OF at])

lemma pt_fresh_bij2:
fixes  pi :: "'x prm"
and     x :: "'a"
and     a :: "'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     a:  "(pi\<bullet>a)\<sharp>(pi\<bullet>x)"
shows  "a\<sharp>x"
using a by (simp add: pt_fresh_bij[OF pt, OF at])

lemma pt_fresh_eqvt:
fixes  pi :: "'x prm"
and     x :: "'a"
and     a :: "'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "pi\<bullet>(a\<sharp>x) = (pi\<bullet>a)\<sharp>(pi\<bullet>x)"
by (simp add: perm_bool pt_fresh_bij[OF pt, OF at])

lemma pt_perm_fresh1:
fixes a :: "'x"
and   b :: "'x"
and   x :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE ('x)"
and     a1: "\<not>(a\<sharp>x)"
and     a2: "b\<sharp>x"
shows "[(a,b)]\<bullet>x \<noteq> x"
proof
assume neg: "[(a,b)]\<bullet>x = x"
from a1 have a1':"a\<in>(supp x)" by (simp add: fresh_def)
from a2 have a2':"b\<notin>(supp x)" by (simp add: fresh_def)
from a1' a2' have a3: "a\<noteq>b" by force
from a1' have "([(a,b)]\<bullet>a)\<in>([(a,b)]\<bullet>(supp x))"
by (simp only: pt_set_bij[OF at_pt_inst[OF at], OF at])
hence "b\<in>([(a,b)]\<bullet>(supp x))" by (simp add: at_calc[OF at])
hence "b\<in>(supp ([(a,b)]\<bullet>x))" by (simp add: pt_perm_supp[OF pt,OF at])
with a2' neg show False by simp
qed

(* the next two lemmas are needed in the proof *)
(* of the structural induction principle       *)
lemma pt_fresh_aux:
fixes a::"'x"
and   b::"'x"
and   c::"'x"
and   x::"'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE ('x)"
assumes a1: "c\<noteq>a" and  a2: "a\<sharp>x" and a3: "c\<sharp>x"
shows "c\<sharp>([(a,b)]\<bullet>x)"
using a1 a2 a3 by (simp_all add: pt_fresh_left[OF pt, OF at] at_calc[OF at])

lemma pt_fresh_aux_ineq:
fixes pi::"'x prm"
and   c::"'y"
and   x::"'a"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('y) TYPE('x)"
and     at:  "at TYPE('x)"
and     cp:  "cp TYPE('a) TYPE('x) TYPE('y)"
and     dj:  "disjoint TYPE('y) TYPE('x)"
assumes a: "c\<sharp>x"
shows "c\<sharp>(pi\<bullet>x)"
using a by (simp add: pt_fresh_left_ineq[OF pta, OF ptb, OF at, OF cp] dj_perm_forget[OF dj])

lemma pt_fresh_eqvt_ineq:
fixes pi::"'x prm"
and   c::"'y"
and   x::"'a"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('y) TYPE('x)"
and     at:  "at TYPE('x)"
and     cp:  "cp TYPE('a) TYPE('x) TYPE('y)"
and     dj:  "disjoint TYPE('y) TYPE('x)"
shows "pi\<bullet>(c\<sharp>x) = (pi\<bullet>c)\<sharp>(pi\<bullet>x)"
by (simp add: pt_fresh_left_ineq[OF pta, OF ptb, OF at, OF cp] dj_perm_forget[OF dj] perm_bool)

-- "three helper lemmas for the perm_fresh_fresh-lemma"
lemma comprehension_neg_UNIV: "{b. \<not> P b} = UNIV - {b. P b}"
by (auto)

lemma infinite_or_neg_infinite:
assumes h:"infinite (UNIV::'a set)"
shows "infinite {b::'a. P b} \<or> infinite {b::'a. \<not> P b}"
proof (subst comprehension_neg_UNIV, case_tac "finite {b. P b}")
assume j:"finite {b::'a. P b}"
have "infinite ((UNIV::'a set) - {b::'a. P b})"
using Diff_infinite_finite[OF j h] by auto
thus "infinite {b::'a. P b} \<or> infinite (UNIV - {b::'a. P b})" ..
next
assume j:"infinite {b::'a. P b}"
thus "infinite {b::'a. P b} \<or> infinite (UNIV - {b::'a. P b})" by simp
qed

--"the co-set of a finite set is infinte"
lemma finite_infinite:
assumes a: "finite {b::'x. P b}"
and     b: "infinite (UNIV::'x set)"
shows "infinite {b. \<not>P b}"
using a and infinite_or_neg_infinite[OF b] by simp

lemma pt_fresh_fresh:
fixes   x :: "'a"
and     a :: "'x"
and     b :: "'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE ('x)"
and     a1: "a\<sharp>x" and a2: "b\<sharp>x"
shows "[(a,b)]\<bullet>x=x"
proof (cases "a=b")
assume "a=b"
hence "[(a,b)] \<triangleq> []" by (simp add: at_ds1[OF at])
hence "[(a,b)]\<bullet>x=([]::'x prm)\<bullet>x" by (rule pt3[OF pt])
thus ?thesis by (simp only: pt1[OF pt])
next
assume c2: "a\<noteq>b"
from a1 have f1: "finite {c. [(a,c)]\<bullet>x \<noteq> x}" by (simp add: fresh_def supp_def)
from a2 have f2: "finite {c. [(b,c)]\<bullet>x \<noteq> x}" by (simp add: fresh_def supp_def)
from f1 and f2 have f3: "finite {c. perm [(a,c)] x \<noteq> x \<or> perm [(b,c)] x \<noteq> x}"
by (force simp only: Collect_disj_eq)
have "infinite {c. [(a,c)]\<bullet>x = x \<and> [(b,c)]\<bullet>x = x}"
by (simp add: finite_infinite[OF f3,OF at4[OF at], simplified])
hence "infinite ({c. [(a,c)]\<bullet>x = x \<and> [(b,c)]\<bullet>x = x}-{a,b})"
by (force dest: Diff_infinite_finite)
hence "({c. [(a,c)]\<bullet>x = x \<and> [(b,c)]\<bullet>x = x}-{a,b}) \<noteq> {}"
by (auto iff del: finite_Diff_insert Diff_eq_empty_iff)
hence "\<exists>c. c\<in>({c. [(a,c)]\<bullet>x = x \<and> [(b,c)]\<bullet>x = x}-{a,b})" by (force)
then obtain c
where eq1: "[(a,c)]\<bullet>x = x"
and eq2: "[(b,c)]\<bullet>x = x"
and ineq: "a\<noteq>c \<and> b\<noteq>c"
by (force)
hence "[(a,c)]\<bullet>([(b,c)]\<bullet>([(a,c)]\<bullet>x)) = x" by simp
hence eq3: "[(a,c),(b,c),(a,c)]\<bullet>x = x" by (simp add: pt2[OF pt,symmetric])
from c2 ineq have "[(a,c),(b,c),(a,c)] \<triangleq> [(a,b)]" by (simp add: at_ds3[OF at])
hence "[(a,c),(b,c),(a,c)]\<bullet>x = [(a,b)]\<bullet>x" by (rule pt3[OF pt])
thus ?thesis using eq3 by simp
qed

lemma pt_perm_compose:
fixes pi1 :: "'x prm"
and   pi2 :: "'x prm"
and   x  :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "pi2\<bullet>(pi1\<bullet>x) = (pi2\<bullet>pi1)\<bullet>(pi2\<bullet>x)"
proof -
have "(pi2@pi1) \<triangleq> ((pi2\<bullet>pi1)@pi2)" by (rule at_ds8)
hence "(pi2@pi1)\<bullet>x = ((pi2\<bullet>pi1)@pi2)\<bullet>x" by (rule pt3[OF pt])
thus ?thesis by (simp add: pt2[OF pt])
qed

lemma pt_perm_compose':
fixes pi1 :: "'x prm"
and   pi2 :: "'x prm"
and   x  :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "(pi2\<bullet>pi1)\<bullet>x = pi2\<bullet>(pi1\<bullet>((rev pi2)\<bullet>x))"
proof -
have "pi2\<bullet>(pi1\<bullet>((rev pi2)\<bullet>x)) = (pi2\<bullet>pi1)\<bullet>(pi2\<bullet>((rev pi2)\<bullet>x))"
by (rule pt_perm_compose[OF pt, OF at])
also have "\<dots> = (pi2\<bullet>pi1)\<bullet>x" by (simp add: pt_pi_rev[OF pt, OF at])
finally have "pi2\<bullet>(pi1\<bullet>((rev pi2)\<bullet>x)) = (pi2\<bullet>pi1)\<bullet>x" by simp
thus ?thesis by simp
qed

lemma pt_perm_compose_rev:
fixes pi1 :: "'x prm"
and   pi2 :: "'x prm"
and   x  :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "(rev pi2)\<bullet>((rev pi1)\<bullet>x) = (rev pi1)\<bullet>(rev (pi1\<bullet>pi2)\<bullet>x)"
proof -
have "((rev pi2)@(rev pi1)) \<triangleq> ((rev pi1)@(rev (pi1\<bullet>pi2)))" by (rule at_ds9[OF at])
hence "((rev pi2)@(rev pi1))\<bullet>x = ((rev pi1)@(rev (pi1\<bullet>pi2)))\<bullet>x" by (rule pt3[OF pt])
thus ?thesis by (simp add: pt2[OF pt])
qed

section {* equivaraince for some connectives *}

lemma pt_all_eqvt:
fixes  pi :: "'x prm"
and     x :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "pi\<bullet>(\<forall>(x::'a). P x) = (\<forall>(x::'a). pi\<bullet>(P ((rev pi)\<bullet>x)))"
apply(drule_tac x="pi\<bullet>x" in spec)
apply(simp add: pt_rev_pi[OF pt, OF at])
done

lemma pt_ex_eqvt:
fixes  pi :: "'x prm"
and     x :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "pi\<bullet>(\<exists>(x::'a). P x) = (\<exists>(x::'a). pi\<bullet>(P ((rev pi)\<bullet>x)))"
apply(rule_tac x="pi\<bullet>x" in exI)
apply(simp add: pt_rev_pi[OF pt, OF at])
done

section {* facts about supports *}
(*==============================*)

lemma supports_subset:
fixes x  :: "'a"
and   S1 :: "'x set"
and   S2 :: "'x set"
assumes  a: "S1 supports x"
and      b: "S1 \<subseteq> S2"
shows "S2 supports x"
using a b
by (force simp add: "op supports_def")

lemma supp_is_subset:
fixes S :: "'x set"
and   x :: "'a"
assumes a1: "S supports x"
and     a2: "finite S"
shows "(supp x)\<subseteq>S"
proof (rule ccontr)
assume "\<not>(supp x \<subseteq> S)"
hence "\<exists>a. a\<in>(supp x) \<and> a\<notin>S" by force
then obtain a where b1: "a\<in>supp x" and b2: "a\<notin>S" by force
from a1 b2 have "\<forall>b. (b\<notin>S \<longrightarrow> ([(a,b)]\<bullet>x = x))" by (unfold "op supports_def", force)
hence "{b. [(a,b)]\<bullet>x \<noteq> x}\<subseteq>S" by force
with a2 have "finite {b. [(a,b)]\<bullet>x \<noteq> x}" by (simp add: finite_subset)
hence "a\<notin>(supp x)" by (unfold supp_def, auto)
with b1 show False by simp
qed

lemma supp_supports:
fixes x :: "'a"
assumes  pt: "pt TYPE('a) TYPE('x)"
and      at: "at TYPE ('x)"
shows "((supp x)::'x set) supports x"
proof (unfold "op supports_def", intro strip)
fix a b
assume "(a::'x)\<notin>(supp x) \<and> (b::'x)\<notin>(supp x)"
hence "a\<sharp>x" and "b\<sharp>x" by (auto simp add: fresh_def)
thus "[(a,b)]\<bullet>x = x" by (rule pt_fresh_fresh[OF pt, OF at])
qed

lemma supports_finite:
fixes S :: "'x set"
and   x :: "'a"
assumes a1: "S supports x"
and     a2: "finite S"
shows "finite ((supp x)::'x set)"
proof -
have "(supp x)\<subseteq>S" using a1 a2 by (rule supp_is_subset)
thus ?thesis using a2 by (simp add: finite_subset)
qed

lemma supp_is_inter:
fixes  x :: "'a"
assumes  pt: "pt TYPE('a) TYPE('x)"
and      at: "at TYPE ('x)"
and      fs: "fs TYPE('a) TYPE('x)"
shows "((supp x)::'x set) = (\<Inter> {S. finite S \<and> S supports x})"
proof (rule equalityI)
show "((supp x)::'x set) \<subseteq> (\<Inter> {S. finite S \<and> S supports x})"
proof (clarify)
fix S c
assume b: "c\<in>((supp x)::'x set)" and "finite (S::'x set)" and "S supports x"
hence  "((supp x)::'x set)\<subseteq>S" by (simp add: supp_is_subset)
with b show "c\<in>S" by force
qed
next
show "(\<Inter> {S. finite S \<and> S supports x}) \<subseteq> ((supp x)::'x set)"
proof (clarify, simp)
fix c
assume d: "\<forall>(S::'x set). finite S \<and> S supports x \<longrightarrow> c\<in>S"
have "((supp x)::'x set) supports x" by (rule supp_supports[OF pt, OF at])
with d fs1[OF fs] show "c\<in>supp x" by force
qed
qed

lemma supp_is_least_supports:
fixes S :: "'x set"
and   x :: "'a"
assumes  pt: "pt TYPE('a) TYPE('x)"
and      at: "at TYPE ('x)"
and      a1: "S supports x"
and      a2: "finite S"
and      a3: "\<forall>S'. (S' supports x) \<longrightarrow> S\<subseteq>S'"
shows "S = (supp x)"
proof (rule equalityI)
show "((supp x)::'x set)\<subseteq>S" using a1 a2 by (rule supp_is_subset)
next
have "((supp x)::'x set) supports x" by (rule supp_supports[OF pt, OF at])
with a3 show "S\<subseteq>supp x" by force
qed

lemma supports_set:
fixes S :: "'x set"
and   X :: "'a set"
assumes  pt: "pt TYPE('a) TYPE('x)"
and      at: "at TYPE ('x)"
and      a: "\<forall>x\<in>X. (\<forall>(a::'x) (b::'x). a\<notin>S\<and>b\<notin>S \<longrightarrow> ([(a,b)]\<bullet>x)\<in>X)"
shows  "S supports X"
using a
apply(simp add: pt_set_bij1a[OF pt, OF at])
apply(force simp add: pt_swap_bij[OF pt, OF at])
apply(simp add: pt_set_bij1a[OF pt, OF at])
done

lemma supports_fresh:
fixes S :: "'x set"
and   a :: "'x"
and   x :: "'a"
assumes a1: "S supports x"
and     a2: "finite S"
and     a3: "a\<notin>S"
shows "a\<sharp>x"
have "(supp x)\<subseteq>S" using a1 a2 by (rule supp_is_subset)
thus "a\<notin>(supp x)" using a3 by force
qed

lemma at_fin_set_supports:
fixes X::"'x set"
assumes at: "at TYPE('x)"
shows "X supports X"
proof -
have "\<forall>a b. a\<notin>X \<and> b\<notin>X \<longrightarrow> [(a,b)]\<bullet>X = X" by (auto simp add: perm_set_def at_calc[OF at])
then show ?thesis by (simp add: "op supports_def")
qed

lemma infinite_Collection:
assumes a1:"infinite X"
and     a2:"\<forall>b\<in>X. P(b)"
shows "infinite {b\<in>X. P(b)}"
using a1 a2
apply auto
apply (subgoal_tac "infinite (X - {b\<in>X. P b})")
done

lemma at_fin_set_supp:
fixes X::"'x set"
assumes at: "at TYPE('x)"
and     fs: "finite X"
shows "(supp X) = X"
proof (rule subset_antisym)
show "(supp X) \<subseteq> X" using at_fin_set_supports[OF at] using fs by (simp add: supp_is_subset)
next
have inf: "infinite (UNIV-X)" using at4[OF at] fs by (auto simp add: Diff_infinite_finite)
{ fix a::"'x"
assume asm: "a\<in>X"
hence "\<forall>b\<in>(UNIV-X). [(a,b)]\<bullet>X\<noteq>X" by (auto simp add: perm_set_def at_calc[OF at])
with inf have "infinite {b\<in>(UNIV-X). [(a,b)]\<bullet>X\<noteq>X}" by (rule infinite_Collection)
hence "infinite {b. [(a,b)]\<bullet>X\<noteq>X}" by (rule_tac infinite_super, auto)
hence "a\<in>(supp X)" by (simp add: supp_def)
}
then show "X\<subseteq>(supp X)" by blast
qed

section {* Permutations acting on Functions *}
(*==========================================*)

lemma pt_fun_app_eq:
fixes f  :: "'a\<Rightarrow>'b"
and   x  :: "'a"
and   pi :: "'x prm"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "pi\<bullet>(f x) = (pi\<bullet>f)(pi\<bullet>x)"
by (simp add: perm_fun_def pt_rev_pi[OF pt, OF at])

--"sometimes pt_fun_app_eq does too much; this lemma 'corrects it'"
lemma pt_perm:
fixes x  :: "'a"
and   pi1 :: "'x prm"
and   pi2 :: "'x prm"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE ('x)"
shows "(pi1\<bullet>perm pi2)(pi1\<bullet>x) = pi1\<bullet>(pi2\<bullet>x)"
by (simp add: pt_fun_app_eq[OF pt, OF at])

lemma pt_fun_eq:
fixes f  :: "'a\<Rightarrow>'b"
and   pi :: "'x prm"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "(pi\<bullet>f = f) = (\<forall> x. pi\<bullet>(f x) = f (pi\<bullet>x))" (is "?LHS = ?RHS")
proof
assume a: "?LHS"
show "?RHS"
proof
fix x
have "pi\<bullet>(f x) = (pi\<bullet>f)(pi\<bullet>x)" by (simp add: pt_fun_app_eq[OF pt, OF at])
also have "\<dots> = f (pi\<bullet>x)" using a by simp
finally show "pi\<bullet>(f x) = f (pi\<bullet>x)" by simp
qed
next
assume b: "?RHS"
show "?LHS"
proof (rule ccontr)
assume "(pi\<bullet>f) \<noteq> f"
hence "\<exists>x. (pi\<bullet>f) x \<noteq> f x" by (simp add: expand_fun_eq)
then obtain x where b1: "(pi\<bullet>f) x \<noteq> f x" by force
from b have "pi\<bullet>(f ((rev pi)\<bullet>x)) = f (pi\<bullet>((rev pi)\<bullet>x))" by force
hence "(pi\<bullet>f)(pi\<bullet>((rev pi)\<bullet>x)) = f (pi\<bullet>((rev pi)\<bullet>x))"
by (simp add: pt_fun_app_eq[OF pt, OF at])
hence "(pi\<bullet>f) x = f x" by (simp add: pt_pi_rev[OF pt, OF at])
with b1 show "False" by simp
qed
qed

-- "two helper lemmas for the equivariance of functions"
lemma pt_swap_eq_aux:
fixes   y :: "'a"
and    pi :: "'x prm"
assumes pt: "pt TYPE('a) TYPE('x)"
and     a: "\<forall>(a::'x) (b::'x). [(a,b)]\<bullet>y = y"
shows "pi\<bullet>y = y"
proof(induct pi)
case Nil show ?case by (simp add: pt1[OF pt])
next
case (Cons x xs)
have "\<exists>a b. x=(a,b)" by force
then obtain a b where p: "x=(a,b)" by force
assume i: "xs\<bullet>y = y"
have "x#xs = [x]@xs" by simp
hence "(x#xs)\<bullet>y = ([x]@xs)\<bullet>y" by simp
hence "(x#xs)\<bullet>y = [x]\<bullet>(xs\<bullet>y)" by (simp only: pt2[OF pt])
thus ?case using a i p by force
qed

lemma pt_swap_eq:
fixes   y :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
shows "(\<forall>(a::'x) (b::'x). [(a,b)]\<bullet>y = y) = (\<forall>pi::'x prm. pi\<bullet>y = y)"
by (force intro: pt_swap_eq_aux[OF pt])

lemma pt_eqvt_fun1a:
fixes f     :: "'a\<Rightarrow>'b"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('b) TYPE('x)"
and     at:  "at TYPE('x)"
and     a:   "((supp f)::'x set)={}"
shows "\<forall>(pi::'x prm). pi\<bullet>f = f"
proof (intro strip)
fix pi
have "\<forall>a b. a\<notin>((supp f)::'x set) \<and> b\<notin>((supp f)::'x set) \<longrightarrow> (([(a,b)]\<bullet>f) = f)"
by (intro strip, fold fresh_def,
simp add: pt_fresh_fresh[OF pt_fun_inst[OF pta, OF ptb, OF at],OF at])
with a have "\<forall>(a::'x) (b::'x). ([(a,b)]\<bullet>f) = f" by force
hence "\<forall>(pi::'x prm). pi\<bullet>f = f"
by (simp add: pt_swap_eq[OF pt_fun_inst[OF pta, OF ptb, OF at]])
thus "(pi::'x prm)\<bullet>f = f" by simp
qed

lemma pt_eqvt_fun1b:
fixes f     :: "'a\<Rightarrow>'b"
assumes a: "\<forall>(pi::'x prm). pi\<bullet>f = f"
shows "((supp f)::'x set)={}"
using a by (simp add: supp_def)

lemma pt_eqvt_fun1:
fixes f     :: "'a\<Rightarrow>'b"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('b) TYPE('x)"
and     at: "at TYPE('x)"
shows "(((supp f)::'x set)={}) = (\<forall>(pi::'x prm). pi\<bullet>f = f)" (is "?LHS = ?RHS")
by (rule iffI, simp add: pt_eqvt_fun1a[OF pta, OF ptb, OF at], simp add: pt_eqvt_fun1b)

lemma pt_eqvt_fun2a:
fixes f     :: "'a\<Rightarrow>'b"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('b) TYPE('x)"
and     at: "at TYPE('x)"
assumes a: "((supp f)::'x set)={}"
shows "\<forall>(pi::'x prm) (x::'a). pi\<bullet>(f x) = f(pi\<bullet>x)"
proof (intro strip)
fix pi x
from a have b: "\<forall>(pi::'x prm). pi\<bullet>f = f" by (simp add: pt_eqvt_fun1[OF pta, OF ptb, OF at])
have "(pi::'x prm)\<bullet>(f x) = (pi\<bullet>f)(pi\<bullet>x)" by (simp add: pt_fun_app_eq[OF pta, OF at])
with b show "(pi::'x prm)\<bullet>(f x) = f (pi\<bullet>x)" by force
qed

lemma pt_eqvt_fun2b:
fixes f     :: "'a\<Rightarrow>'b"
assumes pt1: "pt TYPE('a) TYPE('x)"
and     pt2: "pt TYPE('b) TYPE('x)"
and     at: "at TYPE('x)"
assumes a: "\<forall>(pi::'x prm) (x::'a). pi\<bullet>(f x) = f(pi\<bullet>x)"
shows "((supp f)::'x set)={}"
proof -
from a have "\<forall>(pi::'x prm). pi\<bullet>f = f" by (simp add: pt_fun_eq[OF pt1, OF at, symmetric])
thus ?thesis by (simp add: supp_def)
qed

lemma pt_eqvt_fun2:
fixes f     :: "'a\<Rightarrow>'b"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('b) TYPE('x)"
and     at: "at TYPE('x)"
shows "(((supp f)::'x set)={}) = (\<forall>(pi::'x prm) (x::'a). pi\<bullet>(f x) = f(pi\<bullet>x))"
by (rule iffI,
simp add: pt_eqvt_fun2a[OF pta, OF ptb, OF at],
simp add: pt_eqvt_fun2b[OF pta, OF ptb, OF at])

lemma pt_supp_fun_subset:
fixes f :: "'a\<Rightarrow>'b"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('b) TYPE('x)"
and     at: "at TYPE('x)"
and     f1: "finite ((supp f)::'x set)"
and     f2: "finite ((supp x)::'x set)"
shows "supp (f x) \<subseteq> (((supp f)\<union>(supp x))::'x set)"
proof -
have s1: "((supp f)\<union>((supp x)::'x set)) supports (f x)"
proof (simp add: "op supports_def", fold fresh_def, auto)
fix a::"'x" and b::"'x"
assume "a\<sharp>f" and "b\<sharp>f"
hence a1: "[(a,b)]\<bullet>f = f"
by (rule pt_fresh_fresh[OF pt_fun_inst[OF pta, OF ptb, OF at], OF at])
assume "a\<sharp>x" and "b\<sharp>x"
hence a2: "[(a,b)]\<bullet>x = x" by (rule pt_fresh_fresh[OF pta, OF at])
from a1 a2 show "[(a,b)]\<bullet>(f x) = (f x)" by (simp add: pt_fun_app_eq[OF pta, OF at])
qed
from f1 f2 have "finite ((supp f)\<union>((supp x)::'x set))" by force
with s1 show ?thesis by (rule supp_is_subset)
qed

lemma pt_empty_supp_fun_subset:
fixes f :: "'a\<Rightarrow>'b"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('b) TYPE('x)"
and     at:  "at TYPE('x)"
and     e:   "(supp f)=({}::'x set)"
shows "supp (f x) \<subseteq> ((supp x)::'x set)"
proof (unfold supp_def, auto)
fix a::"'x"
assume a1: "finite {b. [(a, b)]\<bullet>x \<noteq> x}"
assume "infinite {b. [(a, b)]\<bullet>(f x) \<noteq> f x}"
hence a2: "infinite {b. f ([(a, b)]\<bullet>x) \<noteq> f x}" using e
by (simp add: pt_eqvt_fun2[OF pta, OF ptb, OF at])
have a3: "{b. f ([(a,b)]\<bullet>x) \<noteq> f x}\<subseteq>{b. [(a,b)]\<bullet>x \<noteq> x}" by force
from a1 a2 a3 show False by (force dest: finite_subset)
qed

section {* Facts about the support of finite sets of finitely supported things *}
(*=============================================================================*)

constdefs
X_to_Un_supp :: "('a set) \<Rightarrow> 'x set"
"X_to_Un_supp X \<equiv> \<Union>x\<in>X. ((supp x)::'x set)"

lemma UNION_f_eqvt:
fixes X::"('a set)"
and   f::"'a \<Rightarrow> 'x set"
and   pi::"'x prm"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "pi\<bullet>(\<Union>x\<in>X. f x) = (\<Union>x\<in>(pi\<bullet>X). (pi\<bullet>f) x)"
proof -
have pt_x: "pt TYPE('x) TYPE('x)" by (force intro: at_pt_inst at)
show ?thesis
proof (rule equalityI)
case goal1
show "pi\<bullet>(\<Union>x\<in>X. f x) \<subseteq> (\<Union>x\<in>(pi\<bullet>X). (pi\<bullet>f) x)"
apply(rule_tac x="pi\<bullet>xa" in exI)
apply(rule conjI)
apply(rule_tac x="xa" in exI)
apply(simp)
apply(subgoal_tac "(pi\<bullet>f) (pi\<bullet>xa) = pi\<bullet>(f xa)")(*A*)
apply(simp)
apply(rule pt_set_bij2[OF pt_x, OF at])
apply(assumption)
(*A*)
apply(rule sym)
apply(rule pt_fun_app_eq[OF pt, OF at])
done
next
case goal2
show "(\<Union>x\<in>(pi\<bullet>X). (pi\<bullet>f) x) \<subseteq> pi\<bullet>(\<Union>x\<in>X. f x)"
apply(rule_tac x="(rev pi)\<bullet>x" in exI)
apply(rule conjI)
apply(simp add: pt_pi_rev[OF pt_x, OF at])
apply(rule_tac x="a" in bexI)
apply(simp add: pt_set_bij1[OF pt_x, OF at])
apply(simp add: pt_fun_app_eq[OF pt, OF at])
apply(assumption)
done
qed
qed

lemma X_to_Un_supp_eqvt:
fixes X::"('a set)"
and   pi::"'x prm"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "pi\<bullet>(X_to_Un_supp X) = ((X_to_Un_supp (pi\<bullet>X))::'x set)"
apply(simp add: UNION_f_eqvt[OF pt, OF at] perm_fun_def)
apply(simp add: pt_perm_supp[OF pt, OF at])
apply(simp add: pt_pi_rev[OF pt, OF at])
done

lemma Union_supports_set:
fixes X::"('a set)"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "(\<Union>x\<in>X. ((supp x)::'x set)) supports X"
apply(rule allI)+
apply(rule impI)
apply(erule conjE)
apply(auto)
apply(subgoal_tac "[(a,b)]\<bullet>aa = aa")(*A*)
apply(simp)
apply(rule pt_fresh_fresh[OF pt, OF at])
apply(force)
apply(force)
apply(rule_tac x="x" in exI)
apply(simp)
apply(rule sym)
apply(rule pt_fresh_fresh[OF pt, OF at])
apply(force)+
done

lemma Union_of_fin_supp_sets:
fixes X::"('a set)"
assumes fs: "fs TYPE('a) TYPE('x)"
and     fi: "finite X"
shows "finite (\<Union>x\<in>X. ((supp x)::'x set))"
using fi by (induct, auto simp add: fs1[OF fs])

lemma Union_included_in_supp:
fixes X::"('a set)"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     fs: "fs TYPE('a) TYPE('x)"
and     fi: "finite X"
shows "(\<Union>x\<in>X. ((supp x)::'x set)) \<subseteq> supp X"
proof -
have "supp ((X_to_Un_supp X)::'x set) \<subseteq> ((supp X)::'x set)"
apply(rule pt_empty_supp_fun_subset)
apply(force intro: pt_set_inst at_pt_inst pt at)+
apply(rule pt_eqvt_fun2b)
apply(force intro: pt_set_inst at_pt_inst pt at)+
apply(rule allI)+
apply(rule X_to_Un_supp_eqvt[OF pt, OF at])
done
hence "supp (\<Union>x\<in>X. ((supp x)::'x set)) \<subseteq> ((supp X)::'x set)" by (simp add: X_to_Un_supp_def)
moreover
have "supp (\<Union>x\<in>X. ((supp x)::'x set)) = (\<Union>x\<in>X. ((supp x)::'x set))"
apply(rule at_fin_set_supp[OF at])
apply(rule Union_of_fin_supp_sets[OF fs, OF fi])
done
ultimately show ?thesis by force
qed

lemma supp_of_fin_sets:
fixes X::"('a set)"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     fs: "fs TYPE('a) TYPE('x)"
and     fi: "finite X"
shows "(supp X) = (\<Union>x\<in>X. ((supp x)::'x set))"
apply(rule equalityI)
apply(rule supp_is_subset)
apply(rule Union_supports_set[OF pt, OF at])
apply(rule Union_of_fin_supp_sets[OF fs, OF fi])
apply(rule Union_included_in_supp[OF pt, OF at, OF fs, OF fi])
done

lemma supp_fin_union:
fixes X::"('a set)"
and   Y::"('a set)"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     fs: "fs TYPE('a) TYPE('x)"
and     f1: "finite X"
and     f2: "finite Y"
shows "(supp (X\<union>Y)) = (supp X)\<union>((supp Y)::'x set)"
using f1 f2 by (force simp add: supp_of_fin_sets[OF pt, OF at, OF fs])

lemma supp_fin_insert:
fixes X::"('a set)"
and   x::"'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     fs: "fs TYPE('a) TYPE('x)"
and     f:  "finite X"
shows "(supp (insert x X)) = (supp x)\<union>((supp X)::'x set)"
proof -
have "(supp (insert x X)) = ((supp ({x}\<union>(X::'a set)))::'x set)" by simp
also have "\<dots> = (supp {x})\<union>(supp X)"
by (rule supp_fin_union[OF pt, OF at, OF fs], simp_all add: f)
finally show "(supp (insert x X)) = (supp x)\<union>((supp X)::'x set)"
qed

lemma fresh_fin_union:
fixes X::"('a set)"
and   Y::"('a set)"
and   a::"'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     fs: "fs TYPE('a) TYPE('x)"
and     f1: "finite X"
and     f2: "finite Y"
shows "a\<sharp>(X\<union>Y) = (a\<sharp>X \<and> a\<sharp>Y)"
apply(simp add: supp_fin_union[OF pt, OF at, OF fs, OF f1, OF f2])
done

lemma fresh_fin_insert:
fixes X::"('a set)"
and   x::"'a"
and   a::"'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     fs: "fs TYPE('a) TYPE('x)"
and     f:  "finite X"
shows "a\<sharp>(insert x X) = (a\<sharp>x \<and> a\<sharp>X)"
apply(simp add: supp_fin_insert[OF pt, OF at, OF fs, OF f])
done

lemma fresh_fin_insert1:
fixes X::"('a set)"
and   x::"'a"
and   a::"'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     fs: "fs TYPE('a) TYPE('x)"
and     f:  "finite X"
and     a1:  "a\<sharp>x"
and     a2:  "a\<sharp>X"
shows "a\<sharp>(insert x X)"
using a1 a2
apply(simp add: fresh_fin_insert[OF pt, OF at, OF fs, OF f])
done

lemma pt_list_set_supp:
fixes xs :: "'a list"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     fs: "fs TYPE('a) TYPE('x)"
shows "supp (set xs) = ((supp xs)::'x set)"
proof -
have "supp (set xs) = (\<Union>x\<in>(set xs). ((supp x)::'x set))"
by (rule supp_of_fin_sets[OF pt, OF at, OF fs], rule finite_set)
also have "(\<Union>x\<in>(set xs). ((supp x)::'x set)) = (supp xs)"
proof(induct xs)
case Nil show ?case by (simp add: supp_list_nil)
next
case (Cons h t) thus ?case by (simp add: supp_list_cons)
qed
finally show ?thesis by simp
qed

lemma pt_list_set_fresh:
fixes a :: "'x"
and   xs :: "'a list"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     fs: "fs TYPE('a) TYPE('x)"
shows "a\<sharp>(set xs) = a\<sharp>xs"
by (simp add: fresh_def pt_list_set_supp[OF pt, OF at, OF fs])

section {* composition instances *}
(* ============================= *)

lemma cp_list_inst:
assumes c1: "cp TYPE ('a) TYPE('x) TYPE('y)"
shows "cp TYPE ('a list) TYPE('x) TYPE('y)"
using c1
apply(auto)
apply(induct_tac x)
apply(auto)
done

lemma cp_set_inst:
assumes c1: "cp TYPE ('a) TYPE('x) TYPE('y)"
shows "cp TYPE ('a set) TYPE('x) TYPE('y)"
using c1
apply(auto)
apply(rule_tac x="pi2\<bullet>aa" in exI)
apply(auto)
done

lemma cp_option_inst:
assumes c1: "cp TYPE ('a) TYPE('x) TYPE('y)"
shows "cp TYPE ('a option) TYPE('x) TYPE('y)"
using c1
apply(auto)
apply(case_tac x)
apply(auto)
done

lemma cp_noption_inst:
assumes c1: "cp TYPE ('a) TYPE('x) TYPE('y)"
shows "cp TYPE ('a noption) TYPE('x) TYPE('y)"
using c1
apply(auto)
apply(case_tac x)
apply(auto)
done

lemma cp_unit_inst:
shows "cp TYPE (unit) TYPE('x) TYPE('y)"
done

lemma cp_bool_inst:
shows "cp TYPE (bool) TYPE('x) TYPE('y)"
apply(rule allI)+
apply(induct_tac x)
apply(simp_all)
done

lemma cp_prod_inst:
assumes c1: "cp TYPE ('a) TYPE('x) TYPE('y)"
and     c2: "cp TYPE ('b) TYPE('x) TYPE('y)"
shows "cp TYPE ('a\<times>'b) TYPE('x) TYPE('y)"
using c1 c2
done

lemma cp_fun_inst:
assumes c1: "cp TYPE ('a) TYPE('x) TYPE('y)"
and     c2: "cp TYPE ('b) TYPE('x) TYPE('y)"
and     pt: "pt TYPE ('y) TYPE('x)"
and     at: "at TYPE ('x)"
shows "cp TYPE ('a\<Rightarrow>'b) TYPE('x) TYPE('y)"
using c1 c2
apply(auto simp add: cp_def perm_fun_def expand_fun_eq)
apply(simp add: pt_rev_pi[OF pt_list_inst[OF pt_prod_inst[OF pt, OF pt]], OF at])
done

section {* Andy's freshness lemma *}
(*================================*)

lemma freshness_lemma:
fixes h :: "'x\<Rightarrow>'a"
assumes pta: "pt TYPE('a) TYPE('x)"
and     at:  "at TYPE('x)"
and     f1:  "finite ((supp h)::'x set)"
and     a: "\<exists>a::'x. a\<sharp>(h,h a)"
shows  "\<exists>fr::'a. \<forall>a::'x. a\<sharp>h \<longrightarrow> (h a) = fr"
proof -
have ptb: "pt TYPE('x) TYPE('x)" by (simp add: at_pt_inst[OF at])
have ptc: "pt TYPE('x\<Rightarrow>'a) TYPE('x)" by (simp add: pt_fun_inst[OF ptb, OF pta, OF at])
from a obtain a0 where a1: "a0\<sharp>h" and a2: "a0\<sharp>(h a0)" by (force simp add: fresh_prod)
show ?thesis
proof
let ?fr = "h (a0::'x)"
show "\<forall>(a::'x). (a\<sharp>h \<longrightarrow> ((h a) = ?fr))"
proof (intro strip)
fix a
assume a3: "(a::'x)\<sharp>h"
show "h (a::'x) = h a0"
proof (cases "a=a0")
case True thus "h (a::'x) = h a0" by simp
next
case False
assume "a\<noteq>a0"
hence c1: "a\<notin>((supp a0)::'x set)" by  (simp add: fresh_def[symmetric] at_fresh[OF at])
have c2: "a\<notin>((supp h)::'x set)" using a3 by (simp add: fresh_def)
from c1 c2 have c3: "a\<notin>((supp h)\<union>((supp a0)::'x set))" by force
have f2: "finite ((supp a0)::'x set)" by (simp add: at_supp[OF at])
from f1 f2 have "((supp (h a0))::'x set)\<subseteq>((supp h)\<union>(supp a0))"
by (simp add: pt_supp_fun_subset[OF ptb, OF pta, OF at])
hence "a\<notin>((supp (h a0))::'x set)" using c3 by force
hence "a\<sharp>(h a0)" by (simp add: fresh_def)
with a2 have d1: "[(a0,a)]\<bullet>(h a0) = (h a0)" by (rule pt_fresh_fresh[OF pta, OF at])
from a1 a3 have d2: "[(a0,a)]\<bullet>h = h" by (rule pt_fresh_fresh[OF ptc, OF at])
from d1 have "h a0 = [(a0,a)]\<bullet>(h a0)" by simp
also have "\<dots>= ([(a0,a)]\<bullet>h)([(a0,a)]\<bullet>a0)" by (simp add: pt_fun_app_eq[OF ptb, OF at])
also have "\<dots> = h ([(a0,a)]\<bullet>a0)" using d2 by simp
also have "\<dots> = h a" by (simp add: at_calc[OF at])
finally show "h a = h a0" by simp
qed
qed
qed
qed

lemma freshness_lemma_unique:
fixes h :: "'x\<Rightarrow>'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     f1: "finite ((supp h)::'x set)"
and     a: "\<exists>(a::'x). a\<sharp>(h,h a)"
shows  "\<exists>!(fr::'a). \<forall>(a::'x). a\<sharp>h \<longrightarrow> (h a) = fr"
proof (rule ex_ex1I)
from pt at f1 a show "\<exists>fr::'a. \<forall>a::'x. a\<sharp>h \<longrightarrow> h a = fr" by (simp add: freshness_lemma)
next
fix fr1 fr2
assume b1: "\<forall>a::'x. a\<sharp>h \<longrightarrow> h a = fr1"
assume b2: "\<forall>a::'x. a\<sharp>h \<longrightarrow> h a = fr2"
from a obtain a where "(a::'x)\<sharp>h" by (force simp add: fresh_prod)
with b1 b2 have "h a = fr1 \<and> h a = fr2" by force
thus "fr1 = fr2" by force
qed

-- "packaging the freshness lemma into a function"
constdefs
fresh_fun :: "('x\<Rightarrow>'a)\<Rightarrow>'a"
"fresh_fun (h) \<equiv> THE fr. (\<forall>(a::'x). a\<sharp>h \<longrightarrow> (h a) = fr)"

lemma fresh_fun_app:
fixes h :: "'x\<Rightarrow>'a"
and   a :: "'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     f1: "finite ((supp h)::'x set)"
and     a: "\<exists>(a::'x). a\<sharp>(h,h a)"
and     b: "a\<sharp>h"
shows "(fresh_fun h) = (h a)"
proof (unfold fresh_fun_def, rule the_equality)
show "\<forall>(a'::'x). a'\<sharp>h \<longrightarrow> h a' = h a"
proof (intro strip)
fix a'::"'x"
assume c: "a'\<sharp>h"
from pt at f1 a have "\<exists>(fr::'a). \<forall>(a::'x). a\<sharp>h \<longrightarrow> (h a) = fr" by (rule freshness_lemma)
with b c show "h a' = h a" by force
qed
next
fix fr::"'a"
assume "\<forall>a. a\<sharp>h \<longrightarrow> h a = fr"
with b show "fr = h a" by force
qed

lemma fresh_fun_app':
fixes h :: "'x\<Rightarrow>'a"
and   a :: "'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     f1: "finite ((supp h)::'x set)"
and     a: "a\<sharp>h" "a\<sharp>h a"
shows "(fresh_fun h) = (h a)"
apply(rule fresh_fun_app[OF pt, OF at, OF f1])
apply(auto simp add: fresh_prod intro: a)
done

lemma fresh_fun_equiv_ineq:
fixes h :: "'y\<Rightarrow>'a"
and   pi:: "'x prm"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('y) TYPE('x)"
and     ptb':"pt TYPE('a) TYPE('y)"
and     at:  "at TYPE('x)"
and     at': "at TYPE('y)"
and     cpa: "cp TYPE('a) TYPE('x) TYPE('y)"
and     cpb: "cp TYPE('y) TYPE('x) TYPE('y)"
and     f1: "finite ((supp h)::'y set)"
and     a1: "\<exists>(a::'y). a\<sharp>(h,h a)"
shows "pi\<bullet>(fresh_fun h) = fresh_fun(pi\<bullet>h)" (is "?LHS = ?RHS")
proof -
have ptd: "pt TYPE('y) TYPE('y)" by (simp add: at_pt_inst[OF at'])
have ptc: "pt TYPE('y\<Rightarrow>'a) TYPE('x)" by (simp add: pt_fun_inst[OF ptb, OF pta, OF at])
have cpc: "cp TYPE('y\<Rightarrow>'a) TYPE ('x) TYPE ('y)" by (rule cp_fun_inst[OF cpb,OF cpa])
have f2: "finite ((supp (pi\<bullet>h))::'y set)"
proof -
from f1 have "finite (pi\<bullet>((supp h)::'y set))"
by (simp add: pt_set_finite_ineq[OF ptb, OF at])
thus ?thesis
by (simp add: pt_perm_supp_ineq[OF ptc, OF ptb, OF at, OF cpc])
qed
from a1 obtain a' where c0: "a'\<sharp>(h,h a')" by force
hence c1: "a'\<sharp>h" and c2: "a'\<sharp>(h a')" by (simp_all add: fresh_prod)
have c3: "(pi\<bullet>a')\<sharp>(pi\<bullet>h)" using c1
by (simp add: pt_fresh_bij_ineq[OF ptc, OF ptb, OF at, OF cpc])
have c4: "(pi\<bullet>a')\<sharp>(pi\<bullet>h) (pi\<bullet>a')"
proof -
from c2 have "(pi\<bullet>a')\<sharp>(pi\<bullet>(h a'))"
by (simp add: pt_fresh_bij_ineq[OF pta, OF ptb, OF at,OF cpa])
thus ?thesis by (simp add: pt_fun_app_eq[OF ptb, OF at])
qed
have a2: "\<exists>(a::'y). a\<sharp>(pi\<bullet>h,(pi\<bullet>h) a)" using c3 c4 by (force simp add: fresh_prod)
have d1: "?LHS = pi\<bullet>(h a')" using c1 a1 by (simp add: fresh_fun_app[OF ptb', OF at', OF f1])
have d2: "?RHS = (pi\<bullet>h) (pi\<bullet>a')" using c3 a2
by (simp add: fresh_fun_app[OF ptb', OF at', OF f2])
show ?thesis using d1 d2 by (simp add: pt_fun_app_eq[OF ptb, OF at])
qed

lemma fresh_fun_equiv:
fixes h :: "'x\<Rightarrow>'a"
and   pi:: "'x prm"
assumes pta: "pt TYPE('a) TYPE('x)"
and     at:  "at TYPE('x)"
and     f1:  "finite ((supp h)::'x set)"
and     a1: "\<exists>(a::'x). a\<sharp>(h,h a)"
shows "pi\<bullet>(fresh_fun h) = fresh_fun(pi\<bullet>h)" (is "?LHS = ?RHS")
proof -
have ptb: "pt TYPE('x) TYPE('x)" by (simp add: at_pt_inst[OF at])
have ptc: "pt TYPE('x\<Rightarrow>'a) TYPE('x)" by (simp add: pt_fun_inst[OF ptb, OF pta, OF at])
have f2: "finite ((supp (pi\<bullet>h))::'x set)"
proof -
from f1 have "finite (pi\<bullet>((supp h)::'x set))" by (simp add: pt_set_finite_ineq[OF ptb, OF at])
thus ?thesis by (simp add: pt_perm_supp[OF ptc, OF at])
qed
from a1 obtain a' where c0: "a'\<sharp>(h,h a')" by force
hence c1: "a'\<sharp>h" and c2: "a'\<sharp>(h a')" by (simp_all add: fresh_prod)
have c3: "(pi\<bullet>a')\<sharp>(pi\<bullet>h)" using c1 by (simp add: pt_fresh_bij[OF ptc, OF at])
have c4: "(pi\<bullet>a')\<sharp>(pi\<bullet>h) (pi\<bullet>a')"
proof -
from c2 have "(pi\<bullet>a')\<sharp>(pi\<bullet>(h a'))" by (simp add: pt_fresh_bij[OF pta, OF at])
thus ?thesis by (simp add: pt_fun_app_eq[OF ptb, OF at])
qed
have a2: "\<exists>(a::'x). a\<sharp>(pi\<bullet>h,(pi\<bullet>h) a)" using c3 c4 by (force simp add: fresh_prod)
have d1: "?LHS = pi\<bullet>(h a')" using c1 a1 by (simp add: fresh_fun_app[OF pta, OF at, OF f1])
have d2: "?RHS = (pi\<bullet>h) (pi\<bullet>a')" using c3 a2 by (simp add: fresh_fun_app[OF pta, OF at, OF f2])
show ?thesis using d1 d2 by (simp add: pt_fun_app_eq[OF ptb, OF at])
qed

lemma fresh_fun_supports:
fixes h :: "'x\<Rightarrow>'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     f1: "finite ((supp h)::'x set)"
and     a: "\<exists>(a::'x). a\<sharp>(h,h a)"
shows "((supp h)::'x set) supports (fresh_fun h)"
apply(auto)
apply(simp add: fresh_fun_equiv[OF pt, OF at, OF f1, OF a])
apply(simp add: pt_fresh_fresh[OF pt_fun_inst[OF at_pt_inst[OF at], OF pt], OF at, OF at])
done

section {* Abstraction function *}
(*==============================*)

lemma pt_abs_fun_inst:
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "pt TYPE('x\<Rightarrow>('a noption)) TYPE('x)"
by (rule pt_fun_inst[OF at_pt_inst[OF at],OF pt_noption_inst[OF pt],OF at])

constdefs
abs_fun :: "'x\<Rightarrow>'a\<Rightarrow>('x\<Rightarrow>('a noption))" ("[_]._" [100,100] 100)
"[a].x \<equiv> (\<lambda>b. (if b=a then nSome(x) else (if b\<sharp>x then nSome([(a,b)]\<bullet>x) else nNone)))"

(* FIXME: should be called perm_if and placed close to the definition of permutations on bools *)
lemma abs_fun_if:
fixes pi :: "'x prm"
and   x  :: "'a"
and   y  :: "'a"
and   c  :: "bool"
shows "pi\<bullet>(if c then x else y) = (if c then (pi\<bullet>x) else (pi\<bullet>y))"
by force

lemma abs_fun_pi_ineq:
fixes a  :: "'y"
and   x  :: "'a"
and   pi :: "'x prm"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('y) TYPE('x)"
and     at:  "at TYPE('x)"
and     cp:  "cp TYPE('a) TYPE('x) TYPE('y)"
shows "pi\<bullet>([a].x) = [(pi\<bullet>a)].(pi\<bullet>x)"
apply(simp only: expand_fun_eq)
apply(rule allI)
apply(subgoal_tac "(((rev pi)\<bullet>(xa::'y)) = (a::'y)) = (xa = pi\<bullet>a)")(*A*)
apply(subgoal_tac "(((rev pi)\<bullet>xa)\<sharp>x) = (xa\<sharp>(pi\<bullet>x))")(*B*)
apply(subgoal_tac "pi\<bullet>([(a,(rev pi)\<bullet>xa)]\<bullet>x) = [(pi\<bullet>a,xa)]\<bullet>(pi\<bullet>x)")(*C*)
apply(simp)
(*C*)
apply(simp add: pt_pi_rev[OF ptb, OF at])
(*B*)
apply(simp add: pt_fresh_left_ineq[OF pta, OF ptb, OF at, OF cp])
(*A*)
apply(rule iffI)
apply(rule pt_bij2[OF ptb, OF at, THEN sym])
apply(simp)
apply(rule pt_bij2[OF ptb, OF at])
apply(simp)
done

lemma abs_fun_pi:
fixes a  :: "'x"
and   x  :: "'a"
and   pi :: "'x prm"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "pi\<bullet>([a].x) = [(pi\<bullet>a)].(pi\<bullet>x)"
apply(rule abs_fun_pi_ineq)
apply(rule pt)
apply(rule at_pt_inst)
apply(rule at)+
apply(rule cp_pt_inst)
apply(rule pt)
apply(rule at)
done

lemma abs_fun_eq1:
fixes x  :: "'a"
and   y  :: "'a"
and   a  :: "'x"
shows "([a].x = [a].y) = (x = y)"
apply(drule_tac x="a" in spec)
apply(simp)
done

lemma abs_fun_eq2:
fixes x  :: "'a"
and   y  :: "'a"
and   a  :: "'x"
and   b  :: "'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and at: "at TYPE('x)"
and a1: "a\<noteq>b"
and a2: "[a].x = [b].y"
shows "x=[(a,b)]\<bullet>y \<and> a\<sharp>y"
proof -
from a2 have "\<forall>c::'x. ([a].x) c = ([b].y) c" by (force simp add: expand_fun_eq)
hence "([a].x) a = ([b].y) a" by simp
hence a3: "nSome(x) = ([b].y) a" by (simp add: abs_fun_def)
show "x=[(a,b)]\<bullet>y \<and> a\<sharp>y"
proof (cases "a\<sharp>y")
assume a4: "a\<sharp>y"
hence "x=[(b,a)]\<bullet>y" using a3 a1 by (simp add: abs_fun_def)
moreover
have "[(a,b)]\<bullet>y = [(b,a)]\<bullet>y" by (rule pt3[OF pt], rule at_ds5[OF at])
ultimately show ?thesis using a4 by simp
next
assume "\<not>a\<sharp>y"
hence "nSome(x) = nNone" using a1 a3 by (simp add: abs_fun_def)
hence False by simp
thus ?thesis by simp
qed
qed

lemma abs_fun_eq3:
fixes x  :: "'a"
and   y  :: "'a"
and   a   :: "'x"
and   b   :: "'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and at: "at TYPE('x)"
and a1: "a\<noteq>b"
and a2: "x=[(a,b)]\<bullet>y"
and a3: "a\<sharp>y"
shows "[a].x =[b].y"
proof -
show ?thesis
proof (simp only: abs_fun_def expand_fun_eq, intro strip)
fix c::"'x"
let ?LHS = "if c=a then nSome(x) else if c\<sharp>x then nSome([(a,c)]\<bullet>x) else nNone"
and ?RHS = "if c=b then nSome(y) else if c\<sharp>y then nSome([(b,c)]\<bullet>y) else nNone"
show "?LHS=?RHS"
proof -
have "(c=a) \<or> (c=b) \<or> (c\<noteq>a \<and> c\<noteq>b)" by blast
moreover  --"case c=a"
{ have "nSome(x) = nSome([(a,b)]\<bullet>y)" using a2 by simp
also have "\<dots> = nSome([(b,a)]\<bullet>y)" by (simp, rule pt3[OF pt], rule at_ds5[OF at])
finally have "nSome(x) = nSome([(b,a)]\<bullet>y)" by simp
moreover
assume "c=a"
ultimately have "?LHS=?RHS" using a1 a3 by simp
}
moreover  -- "case c=b"
{ have a4: "y=[(a,b)]\<bullet>x" using a2 by (simp only: pt_swap_bij[OF pt, OF at])
hence "a\<sharp>([(a,b)]\<bullet>x)" using a3 by simp
hence "b\<sharp>x" by (simp add: at_calc[OF at] pt_fresh_left[OF pt, OF at])
moreover
assume "c=b"
ultimately have "?LHS=?RHS" using a1 a4 by simp
}
moreover  -- "case c\<noteq>a \<and> c\<noteq>b"
{ assume a5: "c\<noteq>a \<and> c\<noteq>b"
moreover
have "c\<sharp>x = c\<sharp>y" using a2 a5 by (force simp add: at_calc[OF at] pt_fresh_left[OF pt, OF at])
moreover
have "c\<sharp>y \<longrightarrow> [(a,c)]\<bullet>x = [(b,c)]\<bullet>y"
proof (intro strip)
assume a6: "c\<sharp>y"
have "[(a,c),(b,c),(a,c)] \<triangleq> [(a,b)]" using a1 a5 by (force intro: at_ds3[OF at])
hence "[(a,c)]\<bullet>([(b,c)]\<bullet>([(a,c)]\<bullet>y)) = [(a,b)]\<bullet>y"
by (simp add: pt2[OF pt, symmetric] pt3[OF pt])
hence "[(a,c)]\<bullet>([(b,c)]\<bullet>y) = [(a,b)]\<bullet>y" using a3 a6
by (simp add: pt_fresh_fresh[OF pt, OF at])
hence "[(a,c)]\<bullet>([(b,c)]\<bullet>y) = x" using a2 by simp
hence "[(b,c)]\<bullet>y = [(a,c)]\<bullet>x" by (drule_tac pt_bij1[OF pt, OF at], simp)
thus "[(a,c)]\<bullet>x = [(b,c)]\<bullet>y" by simp
qed
ultimately have "?LHS=?RHS" by simp
}
ultimately show "?LHS = ?RHS" by blast
qed
qed
qed

lemma abs_fun_eq:
fixes x  :: "'a"
and   y  :: "'a"
and   a  :: "'x"
and   b  :: "'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and at: "at TYPE('x)"
shows "([a].x = [b].y) = ((a=b \<and> x=y)\<or>(a\<noteq>b \<and> x=[(a,b)]\<bullet>y \<and> a\<sharp>y))"
proof (rule iffI)
assume b: "[a].x = [b].y"
show "(a=b \<and> x=y)\<or>(a\<noteq>b \<and> x=[(a,b)]\<bullet>y \<and> a\<sharp>y)"
proof (cases "a=b")
case True with b show ?thesis by (simp add: abs_fun_eq1)
next
case False with b show ?thesis by (simp add: abs_fun_eq2[OF pt, OF at])
qed
next
assume "(a=b \<and> x=y)\<or>(a\<noteq>b \<and> x=[(a,b)]\<bullet>y \<and> a\<sharp>y)"
thus "[a].x = [b].y"
proof
assume "a=b \<and> x=y" thus ?thesis by simp
next
assume "a\<noteq>b \<and> x=[(a,b)]\<bullet>y \<and> a\<sharp>y"
thus ?thesis by (simp add: abs_fun_eq3[OF pt, OF at])
qed
qed

lemma abs_fun_eq':
fixes x :: "'a"
and   y :: "'a"
and   c :: "'x"
and   a :: "'x"
and   b :: "'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and at: "at TYPE('x)"
and fr: "c\<noteq>a" "c\<noteq>b" "c\<sharp>x" "c\<sharp>y"
shows "([a].x = [b].y) = ([(a,c)]\<bullet>x = [(b,c)]\<bullet>y)"
proof (rule iffI)
assume eq0: "[a].x = [b].y"
show "[(a,c)]\<bullet>x = [(b,c)]\<bullet>y"
proof (cases "a=b")
case True then show ?thesis using eq0 by (simp add: pt_bij[OF pt, OF at] abs_fun_eq[OF pt, OF at])
next
case False
have ineq: "a\<noteq>b" by fact
with eq0 have eq: "x=[(a,b)]\<bullet>y" and fr': "a\<sharp>y" by (simp_all add: abs_fun_eq[OF pt, OF at])
from eq have "[(a,c)]\<bullet>x = [(a,c)]\<bullet>[(a,b)]\<bullet>y" by (simp add: pt_bij[OF pt, OF at])
also have "\<dots> = ([(a,c)]\<bullet>[(a,b)])\<bullet>([(a,c)]\<bullet>y)" by (rule pt_perm_compose[OF pt, OF at])
also have "\<dots> = [(c,b)]\<bullet>y" using ineq fr fr'
by (simp add: pt_fresh_fresh[OF pt, OF at] at_calc[OF at])
also have "\<dots> = [(b,c)]\<bullet>y" by (rule pt3[OF pt], rule at_ds5[OF at])
finally show ?thesis by simp
qed
next
assume eq: "[(a,c)]\<bullet>x = [(b,c)]\<bullet>y"
thus "[a].x = [b].y"
proof (cases "a=b")
case True then show ?thesis using eq by (simp add: pt_bij[OF pt, OF at] abs_fun_eq[OF pt, OF at])
next
case False
have ineq: "a\<noteq>b" by fact
from fr have "([(a,c)]\<bullet>c)\<sharp>([(a,c)]\<bullet>x)" by (simp add: pt_fresh_bij[OF pt, OF at])
hence "a\<sharp>([(b,c)]\<bullet>y)" using eq fr by (simp add: at_calc[OF at])
hence fr0: "a\<sharp>y" using ineq fr by (simp add: pt_fresh_left[OF pt, OF at] at_calc[OF at])
from eq have "x = (rev [(a,c)])\<bullet>([(b,c)]\<bullet>y)" by (rule pt_bij1[OF pt, OF at])
also have "\<dots> = [(a,c)]\<bullet>([(b,c)]\<bullet>y)" by simp
also have "\<dots> = ([(a,c)]\<bullet>[(b,c)])\<bullet>([(a,c)]\<bullet>y)" by (rule pt_perm_compose[OF pt, OF at])
also have "\<dots> = [(b,a)]\<bullet>y" using ineq fr fr0
by (simp add: pt_fresh_fresh[OF pt, OF at] at_calc[OF at])
also have "\<dots> = [(a,b)]\<bullet>y" by (rule pt3[OF pt], rule at_ds5[OF at])
finally show ?thesis using ineq fr0 by (simp add: abs_fun_eq[OF pt, OF at])
qed
qed

lemma abs_fun_supp_approx:
fixes x :: "'a"
and   a :: "'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "((supp ([a].x))::'x set) \<subseteq> (supp (x,a))"
proof
fix c
assume "c\<in>((supp ([a].x))::'x set)"
hence "infinite {b. [(c,b)]\<bullet>([a].x) \<noteq> [a].x}" by (simp add: supp_def)
hence "infinite {b. [([(c,b)]\<bullet>a)].([(c,b)]\<bullet>x) \<noteq> [a].x}" by (simp add: abs_fun_pi[OF pt, OF at])
moreover
have "{b. [([(c,b)]\<bullet>a)].([(c,b)]\<bullet>x) \<noteq> [a].x} \<subseteq> {b. ([(c,b)]\<bullet>x,[(c,b)]\<bullet>a) \<noteq> (x, a)}" by force
ultimately have "infinite {b. ([(c,b)]\<bullet>x,[(c,b)]\<bullet>a) \<noteq> (x, a)}" by (simp add: infinite_super)
thus "c\<in>(supp (x,a))" by (simp add: supp_def)
qed

lemma abs_fun_finite_supp:
fixes x :: "'a"
and   a :: "'x"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     f:  "finite ((supp x)::'x set)"
shows "finite ((supp ([a].x))::'x set)"
proof -
from f have "finite ((supp (x,a))::'x set)" by (simp add: supp_prod at_supp[OF at])
moreover
have "((supp ([a].x))::'x set) \<subseteq> (supp (x,a))" by (rule abs_fun_supp_approx[OF pt, OF at])
ultimately show ?thesis by (simp add: finite_subset)
qed

lemma fresh_abs_funI1:
fixes  x :: "'a"
and    a :: "'x"
and    b :: "'x"
assumes pt:  "pt TYPE('a) TYPE('x)"
and     at:   "at TYPE('x)"
and f:  "finite ((supp x)::'x set)"
and a1: "b\<sharp>x"
and a2: "a\<noteq>b"
shows "b\<sharp>([a].x)"
proof -
have "\<exists>c::'x. c\<sharp>(b,a,x,[a].x)"
proof (rule at_exists_fresh'[OF at], auto simp add: supp_prod at_supp[OF at] f)
show "finite ((supp ([a].x))::'x set)" using f
by (simp add: abs_fun_finite_supp[OF pt, OF at])
qed
then obtain c where fr1: "c\<noteq>b"
and   fr2: "c\<noteq>a"
and   fr3: "c\<sharp>x"
and   fr4: "c\<sharp>([a].x)"
by (force simp add: fresh_prod at_fresh[OF at])
have e: "[(c,b)]\<bullet>([a].x) = [a].([(c,b)]\<bullet>x)" using a2 fr1 fr2
by (force simp add: abs_fun_pi[OF pt, OF at] at_calc[OF at])
from fr4 have "([(c,b)]\<bullet>c)\<sharp> ([(c,b)]\<bullet>([a].x))"
by (simp add: pt_fresh_bij[OF pt_abs_fun_inst[OF pt, OF at], OF at])
hence "b\<sharp>([a].([(c,b)]\<bullet>x))" using fr1 fr2 e
thus ?thesis using a1 fr3
by (simp add: pt_fresh_fresh[OF pt, OF at])
qed

lemma fresh_abs_funE:
fixes a :: "'x"
and   b :: "'x"
and   x :: "'a"
assumes pt:  "pt TYPE('a) TYPE('x)"
and     at:  "at TYPE('x)"
and     f:  "finite ((supp x)::'x set)"
and     a1: "b\<sharp>([a].x)"
and     a2: "b\<noteq>a"
shows "b\<sharp>x"
proof -
have "\<exists>c::'x. c\<sharp>(b,a,x,[a].x)"
proof (rule at_exists_fresh'[OF at], auto simp add: supp_prod at_supp[OF at] f)
show "finite ((supp ([a].x))::'x set)" using f
by (simp add: abs_fun_finite_supp[OF pt, OF at])
qed
then obtain c where fr1: "b\<noteq>c"
and   fr2: "c\<noteq>a"
and   fr3: "c\<sharp>x"
and   fr4: "c\<sharp>([a].x)" by (force simp add: fresh_prod at_fresh[OF at])
have "[a].x = [(b,c)]\<bullet>([a].x)" using a1 fr4
by (simp add: pt_fresh_fresh[OF pt_abs_fun_inst[OF pt, OF at], OF at])
hence "[a].x = [a].([(b,c)]\<bullet>x)" using fr2 a2
by (force simp add: abs_fun_pi[OF pt, OF at] at_calc[OF at])
hence b: "([(b,c)]\<bullet>x) = x" by (simp add: abs_fun_eq1)
from fr3 have "([(b,c)]\<bullet>c)\<sharp>([(b,c)]\<bullet>x)"
by (simp add: pt_fresh_bij[OF pt, OF at])
thus ?thesis using b fr1 by (simp add: at_calc[OF at])
qed

lemma fresh_abs_funI2:
fixes a :: "'x"
and   x :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     f: "finite ((supp x)::'x set)"
shows "a\<sharp>([a].x)"
proof -
have "\<exists>c::'x. c\<sharp>(a,x)"
by  (rule at_exists_fresh'[OF at], auto simp add: supp_prod at_supp[OF at] f)
then obtain c where fr1: "a\<noteq>c" and fr1_sym: "c\<noteq>a"
and   fr2: "c\<sharp>x" by (force simp add: fresh_prod at_fresh[OF at])
have "c\<sharp>([a].x)" using f fr1 fr2 by (simp add: fresh_abs_funI1[OF pt, OF at])
hence "([(c,a)]\<bullet>c)\<sharp>([(c,a)]\<bullet>([a].x))" using fr1
by (simp only: pt_fresh_bij[OF pt_abs_fun_inst[OF pt, OF at], OF at])
hence a: "a\<sharp>([c].([(c,a)]\<bullet>x))" using fr1_sym
by (simp add: abs_fun_pi[OF pt, OF at] at_calc[OF at])
have "[c].([(c,a)]\<bullet>x) = ([a].x)" using fr1_sym fr2
by (simp add: abs_fun_eq[OF pt, OF at])
thus ?thesis using a by simp
qed

lemma fresh_abs_fun_iff:
fixes a :: "'x"
and   b :: "'x"
and   x :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     f: "finite ((supp x)::'x set)"
shows "(b\<sharp>([a].x)) = (b=a \<or> b\<sharp>x)"
by (auto  dest: fresh_abs_funE[OF pt, OF at,OF f]
intro: fresh_abs_funI1[OF pt, OF at,OF f]
fresh_abs_funI2[OF pt, OF at,OF f])

lemma abs_fun_supp:
fixes a :: "'x"
and   x :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
and     f: "finite ((supp x)::'x set)"
shows "supp ([a].x) = (supp x)-{a}"
by (force simp add: supp_fresh_iff fresh_abs_fun_iff[OF pt, OF at, OF f])

(* maybe needs to be better stated as supp intersection supp *)
lemma abs_fun_supp_ineq:
fixes a :: "'y"
and   x :: "'a"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('y) TYPE('x)"
and     at:  "at TYPE('x)"
and     cp:  "cp TYPE('a) TYPE('x) TYPE('y)"
and     dj:  "disjoint TYPE('y) TYPE('x)"
shows "((supp ([a].x))::'x set) = (supp x)"
apply(auto simp add: abs_fun_pi_ineq[OF pta, OF ptb, OF at, OF cp])
done

lemma fresh_abs_fun_iff_ineq:
fixes a :: "'y"
and   b :: "'x"
and   x :: "'a"
assumes pta: "pt TYPE('a) TYPE('x)"
and     ptb: "pt TYPE('y) TYPE('x)"
and     at:  "at TYPE('x)"
and     cp:  "cp TYPE('a) TYPE('x) TYPE('y)"
and     dj:  "disjoint TYPE('y) TYPE('x)"
shows "b\<sharp>([a].x) = b\<sharp>x"
by (simp add: fresh_def abs_fun_supp_ineq[OF pta, OF ptb, OF at, OF cp, OF dj])

section {* abstraction type for the parsing in nominal datatype *}
(*==============================================================*)
consts
"ABS_set" :: "('x\<Rightarrow>('a noption)) set"
inductive ABS_set
intros
ABS_in: "(abs_fun a x)\<in>ABS_set"

typedef (ABS) ('x,'a) ABS = "ABS_set::('x\<Rightarrow>('a noption)) set"
proof
fix x::"'a" and a::"'x"
show "(abs_fun a x)\<in> ABS_set" by (rule ABS_in)
qed

syntax ABS :: "type \<Rightarrow> type \<Rightarrow> type" ("\<guillemotleft>_\<guillemotright>_" [1000,1000] 1000)

section {* lemmas for deciding permutation equations *}
(*===================================================*)

lemma perm_aux_fold:
shows "perm_aux pi x = pi\<bullet>x" by (simp only: perm_aux_def)

lemma pt_perm_compose_aux:
fixes pi1 :: "'x prm"
and   pi2 :: "'x prm"
and   x  :: "'a"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "pi2\<bullet>(pi1\<bullet>x) = perm_aux (pi2\<bullet>pi1) (pi2\<bullet>x)"
proof -
have "(pi2@pi1) \<triangleq> ((pi2\<bullet>pi1)@pi2)" by (rule at_ds8)
hence "(pi2@pi1)\<bullet>x = ((pi2\<bullet>pi1)@pi2)\<bullet>x" by (rule pt3[OF pt])
thus ?thesis by (simp add: pt2[OF pt] perm_aux_def)
qed

lemma cp1_aux:
fixes pi1::"'x prm"
and   pi2::"'y prm"
and   x  ::"'a"
assumes cp: "cp TYPE ('a) TYPE('x) TYPE('y)"
shows "pi1\<bullet>(pi2\<bullet>x) = perm_aux (pi1\<bullet>pi2) (pi1\<bullet>x)"
using cp by (simp add: cp_def perm_aux_def)

lemma perm_eq_app:
fixes f  :: "'a\<Rightarrow>'b"
and   x  :: "'a"
and   pi :: "'x prm"
assumes pt: "pt TYPE('a) TYPE('x)"
and     at: "at TYPE('x)"
shows "(pi\<bullet>(f x)=y) = ((pi\<bullet>f)(pi\<bullet>x)=y)"
by (simp add: pt_fun_app_eq[OF pt, OF at])

lemma perm_eq_lam:
fixes f  :: "'a\<Rightarrow>'b"
and   x  :: "'a"
and   pi :: "'x prm"
shows "((pi\<bullet>(\<lambda>x. f x))=y) = ((\<lambda>x. (pi\<bullet>(f ((rev pi)\<bullet>x))))=y)"

section {* test *}
lemma at_prm_eq_compose:
fixes pi1 :: "'x prm"
and   pi2 :: "'x prm"
and   pi3 :: "'x prm"
assumes at: "at TYPE('x)"
and     a: "pi1 \<triangleq> pi2"
shows "(pi3\<bullet>pi1) \<triangleq> (pi3\<bullet>pi2)"
proof -
have pt: "pt TYPE('x) TYPE('x)" by (rule at_pt_inst[OF at])
have pt_prm: "pt TYPE('x prm) TYPE('x)"
by (rule pt_list_inst[OF pt_prod_inst[OF pt, OF pt]])
from a show ?thesis
apply -
apply(rule_tac pi="rev pi3" in pt_bij4[OF pt, OF at])
apply(rule trans)
apply(rule pt_perm_compose[OF pt, OF at])
apply(simp add: pt_rev_pi[OF pt_prm, OF at])
apply(rule sym)
apply(rule trans)
apply(rule pt_perm_compose[OF pt, OF at])
apply(simp add: pt_rev_pi[OF pt_prm, OF at])
done
qed

(************************)
(* Various eqvt-lemmas  *)

lemma Zero_nat_eqvt:
shows "pi\<bullet>(0::nat) = 0"

lemma One_nat_eqvt:
shows "pi\<bullet>(1::nat) = 1"

lemma Suc_eqvt:
shows "pi\<bullet>(Suc x) = Suc (pi\<bullet>x)"

lemma numeral_nat_eqvt:
shows "pi\<bullet>((number_of n)::nat) = number_of n"

lemma max_nat_eqvt:
fixes x::"nat"
shows "pi\<bullet>(max x y) = max (pi\<bullet>x) (pi\<bullet>y)"

lemma min_nat_eqvt:
fixes x::"nat"
shows "pi\<bullet>(min x y) = min (pi\<bullet>x) (pi\<bullet>y)"

lemma plus_nat_eqvt:
fixes x::"nat"
shows "pi\<bullet>(x + y) = (pi\<bullet>x) + (pi\<bullet>y)"

lemma minus_nat_eqvt:
fixes x::"nat"
shows "pi\<bullet>(x - y) = (pi\<bullet>x) - (pi\<bullet>y)"

lemma mult_nat_eqvt:
fixes x::"nat"
shows "pi\<bullet>(x * y) = (pi\<bullet>x) * (pi\<bullet>y)"

lemma div_nat_eqvt:
fixes x::"nat"
shows "pi\<bullet>(x div y) = (pi\<bullet>x) div (pi\<bullet>y)"

lemma Zero_int_eqvt:
shows "pi\<bullet>(0::int) = 0"

lemma One_int_eqvt:
shows "pi\<bullet>(1::int) = 1"

lemma numeral_int_eqvt:
shows "pi\<bullet>((number_of n)::int) = number_of n"

lemma max_int_eqvt:
fixes x::"int"
shows "pi\<bullet>(max (x::int) y) = max (pi\<bullet>x) (pi\<bullet>y)"

lemma min_int_eqvt:
fixes x::"int"
shows "pi\<bullet>(min x y) = min (pi\<bullet>x) (pi\<bullet>y)"

lemma plus_int_eqvt:
fixes x::"int"
shows "pi\<bullet>(x + y) = (pi\<bullet>x) + (pi\<bullet>y)"

lemma minus_int_eqvt:
fixes x::"int"
shows "pi\<bullet>(x - y) = (pi\<bullet>x) - (pi\<bullet>y)"

lemma mult_int_eqvt:
fixes x::"int"
shows "pi\<bullet>(x * y) = (pi\<bullet>x) * (pi\<bullet>y)"

lemma div_int_eqvt:
fixes x::"int"
shows "pi\<bullet>(x div y) = (pi\<bullet>x) div (pi\<bullet>y)"

(*******************************************************************)
(* Setup of the theorem attributes eqvt, eqvt_force, fresh and bij *)
use "nominal_thmdecls.ML"
setup "NominalThmDecls.setup"

lemmas [eqvt] =
(* connectives *)
if_eqvt imp_eqvt disj_eqvt conj_eqvt neg_eqvt
true_eqvt false_eqvt

(* datatypes *)
perm_unit.simps
perm_list.simps append_eqvt
perm_prod.simps
fst_eqvt snd_eqvt
perm_option.simps

(* nats *)
Suc_eqvt Zero_nat_eqvt One_nat_eqvt min_nat_eqvt max_nat_eqvt
plus_nat_eqvt minus_nat_eqvt mult_nat_eqvt div_nat_eqvt

(* ints *)
Zero_int_eqvt One_int_eqvt min_int_eqvt max_int_eqvt
plus_int_eqvt minus_int_eqvt mult_int_eqvt div_int_eqvt

(* sets *)
union_eqvt empty_eqvt insert_eqvt set_eqvt

(* the lemmas numeral_nat_eqvt numeral_int_eqvt do not conform with the *)
(* usual form of an eqvt-lemma, but they are needed for analysing       *)
(* permutations on nats and ints *)
lemmas [eqvt_force] = numeral_nat_eqvt numeral_int_eqvt

(***************************************)
(* setup for the individial atom-kinds *)
(* and nominal datatypes               *)
use "nominal_atoms.ML"
setup "NominalAtoms.setup"

(************************************************************)
(* various tactics for analysing permutations, supports etc *)
use "nominal_permeq.ML";

method_setup perm_simp =
{* NominalPermeq.perm_simp_meth *}
{* simp rules and simprocs for analysing permutations *}

method_setup perm_simp_debug =
{* NominalPermeq.perm_simp_meth_debug *}
{* simp rules and simprocs for analysing permutations including debugging facilities *}

method_setup perm_full_simp =
{* NominalPermeq.perm_full_simp_meth *}
{* tactic for deciding equalities involving permutations *}

method_setup perm_full_simp_debug =
{* NominalPermeq.perm_full_simp_meth_debug *}
{* tactic for deciding equalities involving permutations including debugging facilities *}

method_setup supports_simp =
{* NominalPermeq.supports_meth *}
{* tactic for deciding whether something supports something else *}

method_setup supports_simp_debug =
{* NominalPermeq.supports_meth_debug *}
{* tactic for deciding whether something supports something else including debugging facilities *}

method_setup finite_guess =
{* NominalPermeq.finite_guess_meth *}
{* tactic for deciding whether something has finite support *}

method_setup finite_guess_debug =
{* NominalPermeq.finite_guess_meth_debug *}
{* tactic for deciding whether something has finite support including debugging facilities *}

method_setup fresh_guess =
{* NominalPermeq.fresh_guess_meth *}
{* tactic for deciding whether an atom is fresh for something*}

method_setup fresh_guess_debug =
{* NominalPermeq.fresh_guess_meth_debug *}
{* tactic for deciding whether an atom is fresh for something including debugging facilities *}

(*****************************************************************)
(* tactics for generating fresh names and simplifying fresh_funs *)
use "nominal_fresh_fun.ML";

method_setup generate_fresh =
{* setup_generate_fresh *}
{* tactic to generate a name fresh for all the variables in the goal *}

method_setup fresh_fun_simp =
{* setup_fresh_fun_simp *}
{* tactic to delete one inner occurence of fresh_fun *}

(************************************************)
(* main file for constructing nominal datatypes *)
use "nominal_package.ML"
setup "NominalPackage.setup"

(******************************************************)
(* primitive recursive functions on nominal datatypes *)
use "nominal_primrec.ML"

(****************************************************)
(* inductive definition involving nominal datatypes *)
use "nominal_inductive.ML"

(*****************************************)
(* setup for induction principles method *)
use "nominal_induct.ML";
method_setup nominal_induct =
{* NominalInduct.nominal_induct_method *}
{* nominal induction *}

end
```