(* Title: HOL/BNF/BNF_Def.thy
Author: Dmitriy Traytel, TU Muenchen
Copyright 2012
Definition of bounded natural functors.
*)
header {* Definition of Bounded Natural Functors *}
theory BNF_Def
imports BNF_Util
keywords
"print_bnfs" :: diag and
"bnf" :: thy_goal
begin
lemma collect_o: "collect F o g = collect ((\<lambda>f. f o g) ` F)"
by (rule ext) (auto simp only: o_apply collect_def)
lemma converse_mono:
"R1 ^-1 \<subseteq> R2 ^-1 \<longleftrightarrow> R1 \<subseteq> R2"
unfolding converse_def by auto
lemma conversep_mono:
"R1 ^--1 \<le> R2 ^--1 \<longleftrightarrow> R1 \<le> R2"
unfolding conversep.simps by auto
lemma converse_shift:
"R1 \<subseteq> R2 ^-1 \<Longrightarrow> R1 ^-1 \<subseteq> R2"
unfolding converse_def by auto
lemma conversep_shift:
"R1 \<le> R2 ^--1 \<Longrightarrow> R1 ^--1 \<le> R2"
unfolding conversep.simps by auto
definition convol ("<_ , _>") where
"<f , g> \<equiv> %a. (f a, g a)"
lemma fst_convol:
"fst o <f , g> = f"
apply(rule ext)
unfolding convol_def by simp
lemma snd_convol:
"snd o <f , g> = g"
apply(rule ext)
unfolding convol_def by simp
lemma convol_mem_GrpI:
"\<lbrakk>g x = g' x; x \<in> A\<rbrakk> \<Longrightarrow> <id , g> x \<in> (Collect (split (Grp A g)))"
unfolding convol_def Grp_def by auto
definition csquare where
"csquare A f1 f2 p1 p2 \<longleftrightarrow> (\<forall> a \<in> A. f1 (p1 a) = f2 (p2 a))"
(* The pullback of sets *)
definition thePull where
"thePull B1 B2 f1 f2 = {(b1,b2). b1 \<in> B1 \<and> b2 \<in> B2 \<and> f1 b1 = f2 b2}"
lemma wpull_thePull:
"wpull (thePull B1 B2 f1 f2) B1 B2 f1 f2 fst snd"
unfolding wpull_def thePull_def by auto
lemma wppull_thePull:
assumes "wppull A B1 B2 f1 f2 e1 e2 p1 p2"
shows
"\<exists> j. \<forall> a' \<in> thePull B1 B2 f1 f2.
j a' \<in> A \<and>
e1 (p1 (j a')) = e1 (fst a') \<and> e2 (p2 (j a')) = e2 (snd a')"
(is "\<exists> j. \<forall> a' \<in> ?A'. ?phi a' (j a')")
proof(rule bchoice[of ?A' ?phi], default)
fix a' assume a': "a' \<in> ?A'"
hence "fst a' \<in> B1" unfolding thePull_def by auto
moreover
from a' have "snd a' \<in> B2" unfolding thePull_def by auto
moreover have "f1 (fst a') = f2 (snd a')"
using a' unfolding csquare_def thePull_def by auto
ultimately show "\<exists> ja'. ?phi a' ja'"
using assms unfolding wppull_def by blast
qed
lemma wpull_wppull:
assumes wp: "wpull A' B1 B2 f1 f2 p1' p2'" and
1: "\<forall> a' \<in> A'. j a' \<in> A \<and> e1 (p1 (j a')) = e1 (p1' a') \<and> e2 (p2 (j a')) = e2 (p2' a')"
shows "wppull A B1 B2 f1 f2 e1 e2 p1 p2"
unfolding wppull_def proof safe
fix b1 b2
assume b1: "b1 \<in> B1" and b2: "b2 \<in> B2" and f: "f1 b1 = f2 b2"
then obtain a' where a': "a' \<in> A'" and b1: "b1 = p1' a'" and b2: "b2 = p2' a'"
using wp unfolding wpull_def by blast
show "\<exists>a\<in>A. e1 (p1 a) = e1 b1 \<and> e2 (p2 a) = e2 b2"
apply (rule bexI[of _ "j a'"]) unfolding b1 b2 using a' 1 by auto
qed
lemma wppull_id: "\<lbrakk>wpull UNIV UNIV UNIV f1 f2 p1 p2; e1 = id; e2 = id\<rbrakk> \<Longrightarrow>
wppull UNIV UNIV UNIV f1 f2 e1 e2 p1 p2"
by (erule wpull_wppull) auto
lemma eq_alt: "op = = Grp UNIV id"
unfolding Grp_def by auto
lemma leq_conversepI: "R = op = \<Longrightarrow> R \<le> R^--1"
by auto
lemma eq_OOI: "R = op = \<Longrightarrow> R = R OO R"
by auto
lemma Grp_UNIV_id: "f = id \<Longrightarrow> (Grp UNIV f)^--1 OO Grp UNIV f = Grp UNIV f"
unfolding Grp_def by auto
lemma Grp_UNIV_idI: "x = y \<Longrightarrow> Grp UNIV id x y"
unfolding Grp_def by auto
lemma Grp_mono: "A \<le> B \<Longrightarrow> Grp A f \<le> Grp B f"
unfolding Grp_def by auto
lemma GrpI: "\<lbrakk>f x = y; x \<in> A\<rbrakk> \<Longrightarrow> Grp A f x y"
unfolding Grp_def by auto
lemma GrpE: "Grp A f x y \<Longrightarrow> (\<lbrakk>f x = y; x \<in> A\<rbrakk> \<Longrightarrow> R) \<Longrightarrow> R"
unfolding Grp_def by auto
lemma Collect_split_Grp_eqD: "z \<in> Collect (split (Grp A f)) \<Longrightarrow> (f \<circ> fst) z = snd z"
unfolding Grp_def o_def by auto
lemma Collect_split_Grp_inD: "z \<in> Collect (split (Grp A f)) \<Longrightarrow> fst z \<in> A"
unfolding Grp_def o_def by auto
lemma wpull_Grp:
"wpull (Collect (split (Grp A f))) A (f ` A) f id fst snd"
unfolding wpull_def Grp_def by auto
definition "pick_middlep P Q a c = (SOME b. P a b \<and> Q b c)"
lemma pick_middlep:
"(P OO Q) a c \<Longrightarrow> P a (pick_middlep P Q a c) \<and> Q (pick_middlep P Q a c) c"
unfolding pick_middlep_def apply(rule someI_ex) by auto
definition fstOp where "fstOp P Q ac = (fst ac, pick_middlep P Q (fst ac) (snd ac))"
definition sndOp where "sndOp P Q ac = (pick_middlep P Q (fst ac) (snd ac), (snd ac))"
lemma fstOp_in: "ac \<in> Collect (split (P OO Q)) \<Longrightarrow> fstOp P Q ac \<in> Collect (split P)"
unfolding fstOp_def mem_Collect_eq
by (subst (asm) surjective_pairing, unfold prod.cases) (erule pick_middlep[THEN conjunct1])
lemma fst_fstOp: "fst bc = (fst \<circ> fstOp P Q) bc"
unfolding comp_def fstOp_def by simp
lemma snd_sndOp: "snd bc = (snd \<circ> sndOp P Q) bc"
unfolding comp_def sndOp_def by simp
lemma sndOp_in: "ac \<in> Collect (split (P OO Q)) \<Longrightarrow> sndOp P Q ac \<in> Collect (split Q)"
unfolding sndOp_def mem_Collect_eq
by (subst (asm) surjective_pairing, unfold prod.cases) (erule pick_middlep[THEN conjunct2])
lemma csquare_fstOp_sndOp:
"csquare (Collect (split (P OO Q))) snd fst (fstOp P Q) (sndOp P Q)"
unfolding csquare_def fstOp_def sndOp_def using pick_middlep by simp
lemma wppull_fstOp_sndOp:
shows "wppull (Collect (split (P OO Q))) (Collect (split P)) (Collect (split Q))
snd fst fst snd (fstOp P Q) (sndOp P Q)"
using pick_middlep unfolding wppull_def fstOp_def sndOp_def relcompp.simps by auto
lemma snd_fst_flip: "snd xy = (fst o (%(x, y). (y, x))) xy"
by (simp split: prod.split)
lemma fst_snd_flip: "fst xy = (snd o (%(x, y). (y, x))) xy"
by (simp split: prod.split)
lemma flip_pred: "A \<subseteq> Collect (split (R ^--1)) \<Longrightarrow> (%(x, y). (y, x)) ` A \<subseteq> Collect (split R)"
by auto
lemma pointfreeE: "f o g = f' o g' \<Longrightarrow> f (g x) = f' (g' x)"
unfolding o_def fun_eq_iff by simp
lemma Collect_split_mono: "A \<le> B \<Longrightarrow> Collect (split A) \<subseteq> Collect (split B)"
by auto
lemma predicate2_cong: "A = B \<Longrightarrow> A a b \<longleftrightarrow> B a b"
by metis
lemma fun_cong_pair: "f = g \<Longrightarrow> f {(a, b). R a b} = g {(a, b). R a b}"
by (rule fun_cong)
lemma flip_as_converse: "{(a, b). R b a} = converse {(a, b). R a b}"
unfolding converse_def mem_Collect_eq prod.cases
apply (rule arg_cong[of _ _ "\<lambda>x. Collect (prod_case x)"])
apply (rule ext)+
apply (unfold conversep_iff)
by (rule refl)
ML_file "Tools/bnf_def_tactics.ML"
ML_file "Tools/bnf_def.ML"
end