Lots of new material about matrices, etc.
(* Title: HOL/Library/Extended_Nonnegative_Real.thy
Author: Johannes Hölzl
*)
subsection \<open>The type of non-negative extended real numbers\<close>
theory Extended_Nonnegative_Real
imports Extended_Real Indicator_Function
begin
lemma ereal_ineq_diff_add:
assumes "b \<noteq> (-\<infinity>::ereal)" "a \<ge> b"
shows "a = b + (a-b)"
by (metis add.commute assms(1) assms(2) ereal_eq_minus_iff ereal_minus_le_iff ereal_plus_eq_PInfty)
lemma Limsup_const_add:
fixes c :: "'a::{complete_linorder, linorder_topology, topological_monoid_add, ordered_ab_semigroup_add}"
shows "F \<noteq> bot \<Longrightarrow> Limsup F (\<lambda>x. c + f x) = c + Limsup F f"
by (rule Limsup_compose_continuous_mono)
(auto intro!: monoI add_mono continuous_on_add continuous_on_id continuous_on_const)
lemma Liminf_const_add:
fixes c :: "'a::{complete_linorder, linorder_topology, topological_monoid_add, ordered_ab_semigroup_add}"
shows "F \<noteq> bot \<Longrightarrow> Liminf F (\<lambda>x. c + f x) = c + Liminf F f"
by (rule Liminf_compose_continuous_mono)
(auto intro!: monoI add_mono continuous_on_add continuous_on_id continuous_on_const)
lemma Liminf_add_const:
fixes c :: "'a::{complete_linorder, linorder_topology, topological_monoid_add, ordered_ab_semigroup_add}"
shows "F \<noteq> bot \<Longrightarrow> Liminf F (\<lambda>x. f x + c) = Liminf F f + c"
by (rule Liminf_compose_continuous_mono)
(auto intro!: monoI add_mono continuous_on_add continuous_on_id continuous_on_const)
lemma sums_offset:
fixes f g :: "nat \<Rightarrow> 'a :: {t2_space, topological_comm_monoid_add}"
assumes "(\<lambda>n. f (n + i)) sums l" shows "f sums (l + (\<Sum>j<i. f j))"
proof -
have "(\<lambda>k. (\<Sum>n<k. f (n + i)) + (\<Sum>j<i. f j)) \<longlonglongrightarrow> l + (\<Sum>j<i. f j)"
using assms by (auto intro!: tendsto_add simp: sums_def)
moreover
{ fix k :: nat
have "(\<Sum>j<k + i. f j) = (\<Sum>j=i..<k + i. f j) + (\<Sum>j=0..<i. f j)"
by (subst sum.union_disjoint[symmetric]) (auto intro!: sum.cong)
also have "(\<Sum>j=i..<k + i. f j) = (\<Sum>j\<in>(\<lambda>n. n + i)`{0..<k}. f j)"
unfolding image_add_atLeastLessThan by simp
finally have "(\<Sum>j<k + i. f j) = (\<Sum>n<k. f (n + i)) + (\<Sum>j<i. f j)"
by (auto simp: inj_on_def atLeast0LessThan sum.reindex) }
ultimately have "(\<lambda>k. (\<Sum>n<k + i. f n)) \<longlonglongrightarrow> l + (\<Sum>j<i. f j)"
by simp
then show ?thesis
unfolding sums_def by (rule LIMSEQ_offset)
qed
lemma suminf_offset:
fixes f g :: "nat \<Rightarrow> 'a :: {t2_space, topological_comm_monoid_add}"
shows "summable (\<lambda>j. f (j + i)) \<Longrightarrow> suminf f = (\<Sum>j. f (j + i)) + (\<Sum>j<i. f j)"
by (intro sums_unique[symmetric] sums_offset summable_sums)
lemma eventually_at_left_1: "(\<And>z::real. 0 < z \<Longrightarrow> z < 1 \<Longrightarrow> P z) \<Longrightarrow> eventually P (at_left 1)"
by (subst eventually_at_left[of 0]) (auto intro: exI[of _ 0])
lemma mult_eq_1:
fixes a b :: "'a :: {ordered_semiring, comm_monoid_mult}"
shows "0 \<le> a \<Longrightarrow> a \<le> 1 \<Longrightarrow> b \<le> 1 \<Longrightarrow> a * b = 1 \<longleftrightarrow> (a = 1 \<and> b = 1)"
by (metis mult.left_neutral eq_iff mult.commute mult_right_mono)
lemma ereal_add_diff_cancel:
fixes a b :: ereal
shows "\<bar>b\<bar> \<noteq> \<infinity> \<Longrightarrow> (a + b) - b = a"
by (cases a b rule: ereal2_cases) auto
lemma add_top:
fixes x :: "'a::{order_top, ordered_comm_monoid_add}"
shows "0 \<le> x \<Longrightarrow> x + top = top"
by (intro top_le add_increasing order_refl)
lemma top_add:
fixes x :: "'a::{order_top, ordered_comm_monoid_add}"
shows "0 \<le> x \<Longrightarrow> top + x = top"
by (intro top_le add_increasing2 order_refl)
lemma le_lfp: "mono f \<Longrightarrow> x \<le> lfp f \<Longrightarrow> f x \<le> lfp f"
by (subst lfp_unfold) (auto dest: monoD)
lemma lfp_transfer:
assumes \<alpha>: "sup_continuous \<alpha>" and f: "sup_continuous f" and mg: "mono g"
assumes bot: "\<alpha> bot \<le> lfp g" and eq: "\<And>x. x \<le> lfp f \<Longrightarrow> \<alpha> (f x) = g (\<alpha> x)"
shows "\<alpha> (lfp f) = lfp g"
proof (rule antisym)
note mf = sup_continuous_mono[OF f]
have f_le_lfp: "(f ^^ i) bot \<le> lfp f" for i
by (induction i) (auto intro: le_lfp mf)
have "\<alpha> ((f ^^ i) bot) \<le> lfp g" for i
by (induction i) (auto simp: bot eq f_le_lfp intro!: le_lfp mg)
then show "\<alpha> (lfp f) \<le> lfp g"
unfolding sup_continuous_lfp[OF f]
by (subst \<alpha>[THEN sup_continuousD])
(auto intro!: mono_funpow sup_continuous_mono[OF f] SUP_least)
show "lfp g \<le> \<alpha> (lfp f)"
by (rule lfp_lowerbound) (simp add: eq[symmetric] lfp_fixpoint[OF mf])
qed
lemma sup_continuous_applyD: "sup_continuous f \<Longrightarrow> sup_continuous (\<lambda>x. f x h)"
using sup_continuous_apply[THEN sup_continuous_compose] .
lemma sup_continuous_SUP[order_continuous_intros]:
fixes M :: "_ \<Rightarrow> _ \<Rightarrow> 'a::complete_lattice"
assumes M: "\<And>i. i \<in> I \<Longrightarrow> sup_continuous (M i)"
shows "sup_continuous (SUP i:I. M i)"
unfolding sup_continuous_def by (auto simp add: sup_continuousD[OF M] intro: SUP_commute)
lemma sup_continuous_apply_SUP[order_continuous_intros]:
fixes M :: "_ \<Rightarrow> _ \<Rightarrow> 'a::complete_lattice"
shows "(\<And>i. i \<in> I \<Longrightarrow> sup_continuous (M i)) \<Longrightarrow> sup_continuous (\<lambda>x. SUP i:I. M i x)"
unfolding SUP_apply[symmetric] by (rule sup_continuous_SUP)
lemma sup_continuous_lfp'[order_continuous_intros]:
assumes 1: "sup_continuous f"
assumes 2: "\<And>g. sup_continuous g \<Longrightarrow> sup_continuous (f g)"
shows "sup_continuous (lfp f)"
proof -
have "sup_continuous ((f ^^ i) bot)" for i
proof (induction i)
case (Suc i) then show ?case
by (auto intro!: 2)
qed (simp add: bot_fun_def sup_continuous_const)
then show ?thesis
unfolding sup_continuous_lfp[OF 1] by (intro order_continuous_intros)
qed
lemma sup_continuous_lfp''[order_continuous_intros]:
assumes 1: "\<And>s. sup_continuous (f s)"
assumes 2: "\<And>g. sup_continuous g \<Longrightarrow> sup_continuous (\<lambda>s. f s (g s))"
shows "sup_continuous (\<lambda>x. lfp (f x))"
proof -
have "sup_continuous (\<lambda>x. (f x ^^ i) bot)" for i
proof (induction i)
case (Suc i) then show ?case
by (auto intro!: 2)
qed (simp add: bot_fun_def sup_continuous_const)
then show ?thesis
unfolding sup_continuous_lfp[OF 1] by (intro order_continuous_intros)
qed
lemma mono_INF_fun:
"(\<And>x y. mono (F x y)) \<Longrightarrow> mono (\<lambda>z x. INF y : X x. F x y z :: 'a :: complete_lattice)"
by (auto intro!: INF_mono[OF bexI] simp: le_fun_def mono_def)
lemma continuous_on_max:
fixes f g :: "'a::topological_space \<Rightarrow> 'b::linorder_topology"
shows "continuous_on A f \<Longrightarrow> continuous_on A g \<Longrightarrow> continuous_on A (\<lambda>x. max (f x) (g x))"
by (auto simp: continuous_on_def intro!: tendsto_max)
lemma continuous_on_cmult_ereal:
"\<bar>c::ereal\<bar> \<noteq> \<infinity> \<Longrightarrow> continuous_on A f \<Longrightarrow> continuous_on A (\<lambda>x. c * f x)"
using tendsto_cmult_ereal[of c f "f x" "at x within A" for x]
by (auto simp: continuous_on_def simp del: tendsto_cmult_ereal)
context linordered_nonzero_semiring
begin
lemma of_nat_nonneg [simp]: "0 \<le> of_nat n"
by (induct n) simp_all
lemma of_nat_mono[simp]: "i \<le> j \<Longrightarrow> of_nat i \<le> of_nat j"
by (auto simp add: le_iff_add intro!: add_increasing2)
end
lemma real_of_nat_Sup:
assumes "A \<noteq> {}" "bdd_above A"
shows "of_nat (Sup A) = (SUP a:A. of_nat a :: real)"
proof (intro antisym)
show "(SUP a:A. of_nat a::real) \<le> of_nat (Sup A)"
using assms by (intro cSUP_least of_nat_mono) (auto intro: cSup_upper)
have "Sup A \<in> A"
unfolding Sup_nat_def using assms by (intro Max_in) (auto simp: bdd_above_nat)
then show "of_nat (Sup A) \<le> (SUP a:A. of_nat a::real)"
by (intro cSUP_upper bdd_above_image_mono assms) (auto simp: mono_def)
qed
\<comment> \<open>These generalise their counterparts in \<open>Nat.linordered_semidom_class\<close>\<close>
lemma of_nat_less[simp]:
"m < n \<Longrightarrow> of_nat m < (of_nat n::'a::{linordered_nonzero_semiring, semiring_char_0})"
by (auto simp: less_le)
lemma of_nat_le_iff[simp]:
"of_nat m \<le> (of_nat n::'a::{linordered_nonzero_semiring, semiring_char_0}) \<longleftrightarrow> m \<le> n"
proof (safe intro!: of_nat_mono)
assume "of_nat m \<le> (of_nat n::'a)" then show "m \<le> n"
proof (intro leI notI)
assume "n < m" from less_le_trans[OF of_nat_less[OF this] \<open>of_nat m \<le> of_nat n\<close>] show False
by blast
qed
qed
lemma (in complete_lattice) SUP_sup_const1:
"I \<noteq> {} \<Longrightarrow> (SUP i:I. sup c (f i)) = sup c (SUP i:I. f i)"
using SUP_sup_distrib[of "\<lambda>_. c" I f] by simp
lemma (in complete_lattice) SUP_sup_const2:
"I \<noteq> {} \<Longrightarrow> (SUP i:I. sup (f i) c) = sup (SUP i:I. f i) c"
using SUP_sup_distrib[of f I "\<lambda>_. c"] by simp
lemma one_less_of_natD:
"(1::'a::linordered_semidom) < of_nat n \<Longrightarrow> 1 < n"
using zero_le_one[where 'a='a]
apply (cases n)
apply simp
subgoal for n'
apply (cases n')
apply simp
apply simp
done
done
lemma sum_le_suminf:
fixes f :: "nat \<Rightarrow> 'a::{ordered_comm_monoid_add, linorder_topology}"
shows "summable f \<Longrightarrow> finite I \<Longrightarrow> \<forall>m\<in>- I. 0 \<le> f m \<Longrightarrow> sum f I \<le> suminf f"
by (rule sums_le[OF _ sums_If_finite_set summable_sums]) auto
lemma suminf_eq_SUP_real:
assumes X: "summable X" "\<And>i. 0 \<le> X i" shows "suminf X = (SUP i. \<Sum>n<i. X n::real)"
by (intro LIMSEQ_unique[OF summable_LIMSEQ] X LIMSEQ_incseq_SUP)
(auto intro!: bdd_aboveI2[where M="\<Sum>i. X i"] sum_le_suminf X monoI sum_mono2)
subsection \<open>Defining the extended non-negative reals\<close>
text \<open>Basic definitions and type class setup\<close>
typedef ennreal = "{x :: ereal. 0 \<le> x}"
morphisms enn2ereal e2ennreal'
by auto
definition "e2ennreal x = e2ennreal' (max 0 x)"
lemma enn2ereal_range: "e2ennreal ` {0..} = UNIV"
proof -
have "\<exists>y\<ge>0. x = e2ennreal y" for x
by (cases x) (auto simp: e2ennreal_def max_absorb2)
then show ?thesis
by (auto simp: image_iff Bex_def)
qed
lemma type_definition_ennreal': "type_definition enn2ereal e2ennreal {x. 0 \<le> x}"
using type_definition_ennreal
by (auto simp: type_definition_def e2ennreal_def max_absorb2)
setup_lifting type_definition_ennreal'
declare [[coercion e2ennreal]]
instantiation ennreal :: complete_linorder
begin
lift_definition top_ennreal :: ennreal is top by (rule top_greatest)
lift_definition bot_ennreal :: ennreal is 0 by (rule order_refl)
lift_definition sup_ennreal :: "ennreal \<Rightarrow> ennreal \<Rightarrow> ennreal" is sup by (rule le_supI1)
lift_definition inf_ennreal :: "ennreal \<Rightarrow> ennreal \<Rightarrow> ennreal" is inf by (rule le_infI)
lift_definition Inf_ennreal :: "ennreal set \<Rightarrow> ennreal" is "Inf"
by (rule Inf_greatest)
lift_definition Sup_ennreal :: "ennreal set \<Rightarrow> ennreal" is "sup 0 \<circ> Sup"
by auto
lift_definition less_eq_ennreal :: "ennreal \<Rightarrow> ennreal \<Rightarrow> bool" is "(\<le>)" .
lift_definition less_ennreal :: "ennreal \<Rightarrow> ennreal \<Rightarrow> bool" is "(<)" .
instance
by standard
(transfer ; auto simp: Inf_lower Inf_greatest Sup_upper Sup_least le_max_iff_disj max.absorb1)+
end
lemma pcr_ennreal_enn2ereal[simp]: "pcr_ennreal (enn2ereal x) x"
by (simp add: ennreal.pcr_cr_eq cr_ennreal_def)
lemma rel_fun_eq_pcr_ennreal: "rel_fun (=) pcr_ennreal f g \<longleftrightarrow> f = enn2ereal \<circ> g"
by (auto simp: rel_fun_def ennreal.pcr_cr_eq cr_ennreal_def)
instantiation ennreal :: infinity
begin
definition infinity_ennreal :: ennreal
where
[simp]: "\<infinity> = (top::ennreal)"
instance ..
end
instantiation ennreal :: "{semiring_1_no_zero_divisors, comm_semiring_1}"
begin
lift_definition one_ennreal :: ennreal is 1 by simp
lift_definition zero_ennreal :: ennreal is 0 by simp
lift_definition plus_ennreal :: "ennreal \<Rightarrow> ennreal \<Rightarrow> ennreal" is "(+)" by simp
lift_definition times_ennreal :: "ennreal \<Rightarrow> ennreal \<Rightarrow> ennreal" is "( * )" by simp
instance
by standard (transfer; auto simp: field_simps ereal_right_distrib)+
end
instantiation ennreal :: minus
begin
lift_definition minus_ennreal :: "ennreal \<Rightarrow> ennreal \<Rightarrow> ennreal" is "\<lambda>a b. max 0 (a - b)"
by simp
instance ..
end
instance ennreal :: numeral ..
instantiation ennreal :: inverse
begin
lift_definition inverse_ennreal :: "ennreal \<Rightarrow> ennreal" is inverse
by (rule inverse_ereal_ge0I)
definition divide_ennreal :: "ennreal \<Rightarrow> ennreal \<Rightarrow> ennreal"
where "x div y = x * inverse (y :: ennreal)"
instance ..
end
lemma ennreal_zero_less_one: "0 < (1::ennreal)" \<comment> \<open>TODO: remove\<close>
by transfer auto
instance ennreal :: dioid
proof (standard; transfer)
fix a b :: ereal assume "0 \<le> a" "0 \<le> b" then show "(a \<le> b) = (\<exists>c\<in>Collect ((\<le>) 0). b = a + c)"
unfolding ereal_ex_split Bex_def
by (cases a b rule: ereal2_cases) (auto intro!: exI[of _ "real_of_ereal (b - a)"])
qed
instance ennreal :: ordered_comm_semiring
by standard
(transfer ; auto intro: add_mono mult_mono mult_ac ereal_left_distrib ereal_mult_left_mono)+
instance ennreal :: linordered_nonzero_semiring
proof qed (transfer; simp)
instance ennreal :: strict_ordered_ab_semigroup_add
proof
fix a b c d :: ennreal show "a < b \<Longrightarrow> c < d \<Longrightarrow> a + c < b + d"
by transfer (auto intro!: ereal_add_strict_mono)
qed
declare [[coercion "of_nat :: nat \<Rightarrow> ennreal"]]
lemma e2ennreal_neg: "x \<le> 0 \<Longrightarrow> e2ennreal x = 0"
unfolding zero_ennreal_def e2ennreal_def by (simp add: max_absorb1)
lemma e2ennreal_mono: "x \<le> y \<Longrightarrow> e2ennreal x \<le> e2ennreal y"
by (cases "0 \<le> x" "0 \<le> y" rule: bool.exhaust[case_product bool.exhaust])
(auto simp: e2ennreal_neg less_eq_ennreal.abs_eq eq_onp_def)
lemma enn2ereal_nonneg[simp]: "0 \<le> enn2ereal x"
using ennreal.enn2ereal[of x] by simp
lemma ereal_ennreal_cases:
obtains b where "0 \<le> a" "a = enn2ereal b" | "a < 0"
using e2ennreal'_inverse[of a, symmetric] by (cases "0 \<le> a") (auto intro: enn2ereal_nonneg)
lemma rel_fun_liminf[transfer_rule]: "rel_fun (rel_fun (=) pcr_ennreal) pcr_ennreal liminf liminf"
proof -
have "rel_fun (rel_fun (=) pcr_ennreal) pcr_ennreal (\<lambda>x. sup 0 (liminf x)) liminf"
unfolding liminf_SUP_INF[abs_def] by (transfer_prover_start, transfer_step+; simp)
then show ?thesis
apply (subst (asm) (2) rel_fun_def)
apply (subst (2) rel_fun_def)
apply (auto simp: comp_def max.absorb2 Liminf_bounded rel_fun_eq_pcr_ennreal)
done
qed
lemma rel_fun_limsup[transfer_rule]: "rel_fun (rel_fun (=) pcr_ennreal) pcr_ennreal limsup limsup"
proof -
have "rel_fun (rel_fun (=) pcr_ennreal) pcr_ennreal (\<lambda>x. INF n. sup 0 (SUP i:{n..}. x i)) limsup"
unfolding limsup_INF_SUP[abs_def] by (transfer_prover_start, transfer_step+; simp)
then show ?thesis
unfolding limsup_INF_SUP[abs_def]
apply (subst (asm) (2) rel_fun_def)
apply (subst (2) rel_fun_def)
apply (auto simp: comp_def max.absorb2 Sup_upper2 rel_fun_eq_pcr_ennreal)
apply (subst (asm) max.absorb2)
apply (rule SUP_upper2)
apply auto
done
qed
lemma sum_enn2ereal[simp]: "(\<And>i. i \<in> I \<Longrightarrow> 0 \<le> f i) \<Longrightarrow> (\<Sum>i\<in>I. enn2ereal (f i)) = enn2ereal (sum f I)"
by (induction I rule: infinite_finite_induct) (auto simp: sum_nonneg zero_ennreal.rep_eq plus_ennreal.rep_eq)
lemma transfer_e2ennreal_sum [transfer_rule]:
"rel_fun (rel_fun (=) pcr_ennreal) (rel_fun (=) pcr_ennreal) sum sum"
by (auto intro!: rel_funI simp: rel_fun_eq_pcr_ennreal comp_def)
lemma enn2ereal_of_nat[simp]: "enn2ereal (of_nat n) = ereal n"
by (induction n) (auto simp: zero_ennreal.rep_eq one_ennreal.rep_eq plus_ennreal.rep_eq)
lemma enn2ereal_numeral[simp]: "enn2ereal (numeral a) = numeral a"
apply (subst of_nat_numeral[of a, symmetric])
apply (subst enn2ereal_of_nat)
apply simp
done
lemma transfer_numeral[transfer_rule]: "pcr_ennreal (numeral a) (numeral a)"
unfolding cr_ennreal_def pcr_ennreal_def by auto
subsection \<open>Cancellation simprocs\<close>
lemma ennreal_add_left_cancel: "a + b = a + c \<longleftrightarrow> a = (\<infinity>::ennreal) \<or> b = c"
unfolding infinity_ennreal_def by transfer (simp add: top_ereal_def ereal_add_cancel_left)
lemma ennreal_add_left_cancel_le: "a + b \<le> a + c \<longleftrightarrow> a = (\<infinity>::ennreal) \<or> b \<le> c"
unfolding infinity_ennreal_def by transfer (simp add: ereal_add_le_add_iff top_ereal_def disj_commute)
lemma ereal_add_left_cancel_less:
fixes a b c :: ereal
shows "0 \<le> a \<Longrightarrow> 0 \<le> b \<Longrightarrow> a + b < a + c \<longleftrightarrow> a \<noteq> \<infinity> \<and> b < c"
by (cases a b c rule: ereal3_cases) auto
lemma ennreal_add_left_cancel_less: "a + b < a + c \<longleftrightarrow> a \<noteq> (\<infinity>::ennreal) \<and> b < c"
unfolding infinity_ennreal_def
by transfer (simp add: top_ereal_def ereal_add_left_cancel_less)
ML \<open>
structure Cancel_Ennreal_Common =
struct
(* copied from src/HOL/Tools/nat_numeral_simprocs.ML *)
fun find_first_t _ _ [] = raise TERM("find_first_t", [])
| find_first_t past u (t::terms) =
if u aconv t then (rev past @ terms)
else find_first_t (t::past) u terms
fun dest_summing (Const (@{const_name Groups.plus}, _) $ t $ u, ts) =
dest_summing (t, dest_summing (u, ts))
| dest_summing (t, ts) = t :: ts
val mk_sum = Arith_Data.long_mk_sum
fun dest_sum t = dest_summing (t, [])
val find_first = find_first_t []
val trans_tac = Numeral_Simprocs.trans_tac
val norm_ss =
simpset_of (put_simpset HOL_basic_ss @{context}
addsimps @{thms ac_simps add_0_left add_0_right})
fun norm_tac ctxt = ALLGOALS (simp_tac (put_simpset norm_ss ctxt))
fun simplify_meta_eq ctxt cancel_th th =
Arith_Data.simplify_meta_eq [] ctxt
([th, cancel_th] MRS trans)
fun mk_eq (a, b) = HOLogic.mk_Trueprop (HOLogic.mk_eq (a, b))
end
structure Eq_Ennreal_Cancel = ExtractCommonTermFun
(open Cancel_Ennreal_Common
val mk_bal = HOLogic.mk_eq
val dest_bal = HOLogic.dest_bin @{const_name HOL.eq} @{typ ennreal}
fun simp_conv _ _ = SOME @{thm ennreal_add_left_cancel}
)
structure Le_Ennreal_Cancel = ExtractCommonTermFun
(open Cancel_Ennreal_Common
val mk_bal = HOLogic.mk_binrel @{const_name Orderings.less_eq}
val dest_bal = HOLogic.dest_bin @{const_name Orderings.less_eq} @{typ ennreal}
fun simp_conv _ _ = SOME @{thm ennreal_add_left_cancel_le}
)
structure Less_Ennreal_Cancel = ExtractCommonTermFun
(open Cancel_Ennreal_Common
val mk_bal = HOLogic.mk_binrel @{const_name Orderings.less}
val dest_bal = HOLogic.dest_bin @{const_name Orderings.less} @{typ ennreal}
fun simp_conv _ _ = SOME @{thm ennreal_add_left_cancel_less}
)
\<close>
simproc_setup ennreal_eq_cancel
("(l::ennreal) + m = n" | "(l::ennreal) = m + n") =
\<open>fn phi => fn ctxt => fn ct => Eq_Ennreal_Cancel.proc ctxt (Thm.term_of ct)\<close>
simproc_setup ennreal_le_cancel
("(l::ennreal) + m \<le> n" | "(l::ennreal) \<le> m + n") =
\<open>fn phi => fn ctxt => fn ct => Le_Ennreal_Cancel.proc ctxt (Thm.term_of ct)\<close>
simproc_setup ennreal_less_cancel
("(l::ennreal) + m < n" | "(l::ennreal) < m + n") =
\<open>fn phi => fn ctxt => fn ct => Less_Ennreal_Cancel.proc ctxt (Thm.term_of ct)\<close>
subsection \<open>Order with top\<close>
lemma ennreal_zero_less_top[simp]: "0 < (top::ennreal)"
by transfer (simp add: top_ereal_def)
lemma ennreal_one_less_top[simp]: "1 < (top::ennreal)"
by transfer (simp add: top_ereal_def)
lemma ennreal_zero_neq_top[simp]: "0 \<noteq> (top::ennreal)"
by transfer (simp add: top_ereal_def)
lemma ennreal_top_neq_zero[simp]: "(top::ennreal) \<noteq> 0"
by transfer (simp add: top_ereal_def)
lemma ennreal_top_neq_one[simp]: "top \<noteq> (1::ennreal)"
by transfer (simp add: top_ereal_def one_ereal_def ereal_max[symmetric] del: ereal_max)
lemma ennreal_one_neq_top[simp]: "1 \<noteq> (top::ennreal)"
by transfer (simp add: top_ereal_def one_ereal_def ereal_max[symmetric] del: ereal_max)
lemma ennreal_add_less_top[simp]:
fixes a b :: ennreal
shows "a + b < top \<longleftrightarrow> a < top \<and> b < top"
by transfer (auto simp: top_ereal_def)
lemma ennreal_add_eq_top[simp]:
fixes a b :: ennreal
shows "a + b = top \<longleftrightarrow> a = top \<or> b = top"
by transfer (auto simp: top_ereal_def)
lemma ennreal_sum_less_top[simp]:
fixes f :: "'a \<Rightarrow> ennreal"
shows "finite I \<Longrightarrow> (\<Sum>i\<in>I. f i) < top \<longleftrightarrow> (\<forall>i\<in>I. f i < top)"
by (induction I rule: finite_induct) auto
lemma ennreal_sum_eq_top[simp]:
fixes f :: "'a \<Rightarrow> ennreal"
shows "finite I \<Longrightarrow> (\<Sum>i\<in>I. f i) = top \<longleftrightarrow> (\<exists>i\<in>I. f i = top)"
by (induction I rule: finite_induct) auto
lemma ennreal_mult_eq_top_iff:
fixes a b :: ennreal
shows "a * b = top \<longleftrightarrow> (a = top \<and> b \<noteq> 0) \<or> (b = top \<and> a \<noteq> 0)"
by transfer (auto simp: top_ereal_def)
lemma ennreal_top_eq_mult_iff:
fixes a b :: ennreal
shows "top = a * b \<longleftrightarrow> (a = top \<and> b \<noteq> 0) \<or> (b = top \<and> a \<noteq> 0)"
using ennreal_mult_eq_top_iff[of a b] by auto
lemma ennreal_mult_less_top:
fixes a b :: ennreal
shows "a * b < top \<longleftrightarrow> (a = 0 \<or> b = 0 \<or> (a < top \<and> b < top))"
by transfer (auto simp add: top_ereal_def)
lemma top_power_ennreal: "top ^ n = (if n = 0 then 1 else top :: ennreal)"
by (induction n) (simp_all add: ennreal_mult_eq_top_iff)
lemma ennreal_prod_eq_0[simp]:
fixes f :: "'a \<Rightarrow> ennreal"
shows "(prod f A = 0) = (finite A \<and> (\<exists>i\<in>A. f i = 0))"
by (induction A rule: infinite_finite_induct) auto
lemma ennreal_prod_eq_top:
fixes f :: "'a \<Rightarrow> ennreal"
shows "(\<Prod>i\<in>I. f i) = top \<longleftrightarrow> (finite I \<and> ((\<forall>i\<in>I. f i \<noteq> 0) \<and> (\<exists>i\<in>I. f i = top)))"
by (induction I rule: infinite_finite_induct) (auto simp: ennreal_mult_eq_top_iff)
lemma ennreal_top_mult: "top * a = (if a = 0 then 0 else top :: ennreal)"
by (simp add: ennreal_mult_eq_top_iff)
lemma ennreal_mult_top: "a * top = (if a = 0 then 0 else top :: ennreal)"
by (simp add: ennreal_mult_eq_top_iff)
lemma enn2ereal_eq_top_iff[simp]: "enn2ereal x = \<infinity> \<longleftrightarrow> x = top"
by transfer (simp add: top_ereal_def)
lemma enn2ereal_top[simp]: "enn2ereal top = \<infinity>"
by transfer (simp add: top_ereal_def)
lemma e2ennreal_infty[simp]: "e2ennreal \<infinity> = top"
by (simp add: top_ennreal.abs_eq top_ereal_def)
lemma ennreal_top_minus[simp]: "top - x = (top::ennreal)"
by transfer (auto simp: top_ereal_def max_def)
lemma minus_top_ennreal: "x - top = (if x = top then top else 0:: ennreal)"
apply transfer
subgoal for x
by (cases x) (auto simp: top_ereal_def max_def)
done
lemma bot_ennreal: "bot = (0::ennreal)"
by transfer rule
lemma ennreal_of_nat_neq_top[simp]: "of_nat i \<noteq> (top::ennreal)"
by (induction i) auto
lemma numeral_eq_of_nat: "(numeral a::ennreal) = of_nat (numeral a)"
by simp
lemma of_nat_less_top: "of_nat i < (top::ennreal)"
using less_le_trans[of "of_nat i" "of_nat (Suc i)" "top::ennreal"]
by simp
lemma top_neq_numeral[simp]: "top \<noteq> (numeral i::ennreal)"
using of_nat_less_top[of "numeral i"] by simp
lemma ennreal_numeral_less_top[simp]: "numeral i < (top::ennreal)"
using of_nat_less_top[of "numeral i"] by simp
lemma ennreal_add_bot[simp]: "bot + x = (x::ennreal)"
by transfer simp
instance ennreal :: semiring_char_0
proof (standard, safe intro!: linorder_injI)
have *: "1 + of_nat k \<noteq> (0::ennreal)" for k
using add_pos_nonneg[OF zero_less_one, of "of_nat k :: ennreal"] by auto
fix x y :: nat assume "x < y" "of_nat x = (of_nat y::ennreal)" then show False
by (auto simp add: less_iff_Suc_add *)
qed
subsection \<open>Arithmetic\<close>
lemma ennreal_minus_zero[simp]: "a - (0::ennreal) = a"
by transfer (auto simp: max_def)
lemma ennreal_add_diff_cancel_right[simp]:
fixes x y z :: ennreal shows "y \<noteq> top \<Longrightarrow> (x + y) - y = x"
apply transfer
subgoal for x y
apply (cases x y rule: ereal2_cases)
apply (auto split: split_max simp: top_ereal_def)
done
done
lemma ennreal_add_diff_cancel_left[simp]:
fixes x y z :: ennreal shows "y \<noteq> top \<Longrightarrow> (y + x) - y = x"
by (simp add: add.commute)
lemma
fixes a b :: ennreal
shows "a - b = 0 \<Longrightarrow> a \<le> b"
apply transfer
subgoal for a b
apply (cases a b rule: ereal2_cases)
apply (auto simp: not_le max_def split: if_splits)
done
done
lemma ennreal_minus_cancel:
fixes a b c :: ennreal
shows "c \<noteq> top \<Longrightarrow> a \<le> c \<Longrightarrow> b \<le> c \<Longrightarrow> c - a = c - b \<Longrightarrow> a = b"
apply transfer
subgoal for a b c
by (cases a b c rule: ereal3_cases)
(auto simp: top_ereal_def max_def split: if_splits)
done
lemma sup_const_add_ennreal:
fixes a b c :: "ennreal"
shows "sup (c + a) (c + b) = c + sup a b"
apply transfer
subgoal for a b c
apply (cases a b c rule: ereal3_cases)
apply (auto simp: ereal_max[symmetric] simp del: ereal_max)
done
done
lemma ennreal_diff_add_assoc:
fixes a b c :: ennreal
shows "a \<le> b \<Longrightarrow> c + b - a = c + (b - a)"
apply transfer
subgoal for a b c
by (cases a b c rule: ereal3_cases) (auto simp: field_simps max_absorb2)
done
lemma mult_divide_eq_ennreal:
fixes a b :: ennreal
shows "b \<noteq> 0 \<Longrightarrow> b \<noteq> top \<Longrightarrow> (a * b) / b = a"
unfolding divide_ennreal_def
apply transfer
apply (subst mult.assoc)
apply (simp add: top_ereal_def divide_ereal_def[symmetric])
done
lemma divide_mult_eq: "a \<noteq> 0 \<Longrightarrow> a \<noteq> \<infinity> \<Longrightarrow> x * a / (b * a) = x / (b::ennreal)"
unfolding divide_ennreal_def infinity_ennreal_def
apply transfer
subgoal for a b c
apply (cases a b c rule: ereal3_cases)
apply (auto simp: top_ereal_def)
done
done
lemma ennreal_mult_divide_eq:
fixes a b :: ennreal
shows "b \<noteq> 0 \<Longrightarrow> b \<noteq> top \<Longrightarrow> (a * b) / b = a"
unfolding divide_ennreal_def
apply transfer
apply (subst mult.assoc)
apply (simp add: top_ereal_def divide_ereal_def[symmetric])
done
lemma ennreal_add_diff_cancel:
fixes a b :: ennreal
shows "b \<noteq> \<infinity> \<Longrightarrow> (a + b) - b = a"
unfolding infinity_ennreal_def
by transfer (simp add: max_absorb2 top_ereal_def ereal_add_diff_cancel)
lemma ennreal_minus_eq_0:
"a - b = 0 \<Longrightarrow> a \<le> (b::ennreal)"
apply transfer
subgoal for a b
apply (cases a b rule: ereal2_cases)
apply (auto simp: zero_ereal_def ereal_max[symmetric] max.absorb2 simp del: ereal_max)
done
done
lemma ennreal_mono_minus_cancel:
fixes a b c :: ennreal
shows "a - b \<le> a - c \<Longrightarrow> a < top \<Longrightarrow> b \<le> a \<Longrightarrow> c \<le> a \<Longrightarrow> c \<le> b"
by transfer
(auto simp add: max.absorb2 ereal_diff_positive top_ereal_def dest: ereal_mono_minus_cancel)
lemma ennreal_mono_minus:
fixes a b c :: ennreal
shows "c \<le> b \<Longrightarrow> a - b \<le> a - c"
apply transfer
apply (rule max.mono)
apply simp
subgoal for a b c
by (cases a b c rule: ereal3_cases) auto
done
lemma ennreal_minus_pos_iff:
fixes a b :: ennreal
shows "a < top \<or> b < top \<Longrightarrow> 0 < a - b \<Longrightarrow> b < a"
apply transfer
subgoal for a b
by (cases a b rule: ereal2_cases) (auto simp: less_max_iff_disj)
done
lemma ennreal_inverse_top[simp]: "inverse top = (0::ennreal)"
by transfer (simp add: top_ereal_def ereal_inverse_eq_0)
lemma ennreal_inverse_zero[simp]: "inverse 0 = (top::ennreal)"
by transfer (simp add: top_ereal_def ereal_inverse_eq_0)
lemma ennreal_top_divide: "top / (x::ennreal) = (if x = top then 0 else top)"
unfolding divide_ennreal_def
by transfer (simp add: top_ereal_def ereal_inverse_eq_0 ereal_0_gt_inverse)
lemma ennreal_zero_divide[simp]: "0 / (x::ennreal) = 0"
by (simp add: divide_ennreal_def)
lemma ennreal_divide_zero[simp]: "x / (0::ennreal) = (if x = 0 then 0 else top)"
by (simp add: divide_ennreal_def ennreal_mult_top)
lemma ennreal_divide_top[simp]: "x / (top::ennreal) = 0"
by (simp add: divide_ennreal_def ennreal_top_mult)
lemma ennreal_times_divide: "a * (b / c) = a * b / (c::ennreal)"
unfolding divide_ennreal_def
by transfer (simp add: divide_ereal_def[symmetric] ereal_times_divide_eq)
lemma ennreal_zero_less_divide: "0 < a / b \<longleftrightarrow> (0 < a \<and> b < (top::ennreal))"
unfolding divide_ennreal_def
by transfer (auto simp: ereal_zero_less_0_iff top_ereal_def ereal_0_gt_inverse)
lemma divide_right_mono_ennreal:
fixes a b c :: ennreal
shows "a \<le> b \<Longrightarrow> a / c \<le> b / c"
unfolding divide_ennreal_def by (intro mult_mono) auto
lemma ennreal_mult_strict_right_mono: "(a::ennreal) < c \<Longrightarrow> 0 < b \<Longrightarrow> b < top \<Longrightarrow> a * b < c * b"
by transfer (auto intro!: ereal_mult_strict_right_mono)
lemma ennreal_indicator_less[simp]:
"indicator A x \<le> (indicator B x::ennreal) \<longleftrightarrow> (x \<in> A \<longrightarrow> x \<in> B)"
by (simp add: indicator_def not_le)
lemma ennreal_inverse_positive: "0 < inverse x \<longleftrightarrow> (x::ennreal) \<noteq> top"
by transfer (simp add: ereal_0_gt_inverse top_ereal_def)
lemma ennreal_inverse_mult': "((0 < b \<or> a < top) \<and> (0 < a \<or> b < top)) \<Longrightarrow> inverse (a * b::ennreal) = inverse a * inverse b"
apply transfer
subgoal for a b
by (cases a b rule: ereal2_cases) (auto simp: top_ereal_def)
done
lemma ennreal_inverse_mult: "a < top \<Longrightarrow> b < top \<Longrightarrow> inverse (a * b::ennreal) = inverse a * inverse b"
apply transfer
subgoal for a b
by (cases a b rule: ereal2_cases) (auto simp: top_ereal_def)
done
lemma ennreal_inverse_1[simp]: "inverse (1::ennreal) = 1"
by transfer simp
lemma ennreal_inverse_eq_0_iff[simp]: "inverse (a::ennreal) = 0 \<longleftrightarrow> a = top"
by transfer (simp add: ereal_inverse_eq_0 top_ereal_def)
lemma ennreal_inverse_eq_top_iff[simp]: "inverse (a::ennreal) = top \<longleftrightarrow> a = 0"
by transfer (simp add: top_ereal_def)
lemma ennreal_divide_eq_0_iff[simp]: "(a::ennreal) / b = 0 \<longleftrightarrow> (a = 0 \<or> b = top)"
by (simp add: divide_ennreal_def)
lemma ennreal_divide_eq_top_iff: "(a::ennreal) / b = top \<longleftrightarrow> ((a \<noteq> 0 \<and> b = 0) \<or> (a = top \<and> b \<noteq> top))"
by (auto simp add: divide_ennreal_def ennreal_mult_eq_top_iff)
lemma one_divide_one_divide_ennreal[simp]: "1 / (1 / c) = (c::ennreal)"
including ennreal.lifting
unfolding divide_ennreal_def
by transfer auto
lemma ennreal_mult_left_cong:
"((a::ennreal) \<noteq> 0 \<Longrightarrow> b = c) \<Longrightarrow> a * b = a * c"
by (cases "a = 0") simp_all
lemma ennreal_mult_right_cong:
"((a::ennreal) \<noteq> 0 \<Longrightarrow> b = c) \<Longrightarrow> b * a = c * a"
by (cases "a = 0") simp_all
lemma ennreal_zero_less_mult_iff: "0 < a * b \<longleftrightarrow> 0 < a \<and> 0 < (b::ennreal)"
by transfer (auto simp add: ereal_zero_less_0_iff le_less)
lemma less_diff_eq_ennreal:
fixes a b c :: ennreal
shows "b < top \<or> c < top \<Longrightarrow> a < b - c \<longleftrightarrow> a + c < b"
apply transfer
subgoal for a b c
by (cases a b c rule: ereal3_cases) (auto split: split_max)
done
lemma diff_add_cancel_ennreal:
fixes a b :: ennreal shows "a \<le> b \<Longrightarrow> b - a + a = b"
unfolding infinity_ennreal_def
apply transfer
subgoal for a b
by (cases a b rule: ereal2_cases) (auto simp: max_absorb2)
done
lemma ennreal_diff_self[simp]: "a \<noteq> top \<Longrightarrow> a - a = (0::ennreal)"
by transfer (simp add: top_ereal_def)
lemma ennreal_minus_mono:
fixes a b c :: ennreal
shows "a \<le> c \<Longrightarrow> d \<le> b \<Longrightarrow> a - b \<le> c - d"
apply transfer
apply (rule max.mono)
apply simp
subgoal for a b c d
by (cases a b c d rule: ereal3_cases[case_product ereal_cases]) auto
done
lemma ennreal_minus_eq_top[simp]: "a - (b::ennreal) = top \<longleftrightarrow> a = top"
by transfer (auto simp: top_ereal_def max.absorb2 ereal_minus_eq_PInfty_iff split: split_max)
lemma ennreal_divide_self[simp]: "a \<noteq> 0 \<Longrightarrow> a < top \<Longrightarrow> a / a = (1::ennreal)"
unfolding divide_ennreal_def
apply transfer
subgoal for a
by (cases a) (auto simp: top_ereal_def)
done
subsection \<open>Coercion from @{typ real} to @{typ ennreal}\<close>
lift_definition ennreal :: "real \<Rightarrow> ennreal" is "sup 0 \<circ> ereal"
by simp
declare [[coercion ennreal]]
lemma ennreal_cong: "x = y \<Longrightarrow> ennreal x = ennreal y" by simp
lemma ennreal_cases[cases type: ennreal]:
fixes x :: ennreal
obtains (real) r :: real where "0 \<le> r" "x = ennreal r" | (top) "x = top"
apply transfer
subgoal for x thesis
by (cases x) (auto simp: max.absorb2 top_ereal_def)
done
lemmas ennreal2_cases = ennreal_cases[case_product ennreal_cases]
lemmas ennreal3_cases = ennreal_cases[case_product ennreal2_cases]
lemma ennreal_neq_top[simp]: "ennreal r \<noteq> top"
by transfer (simp add: top_ereal_def zero_ereal_def ereal_max[symmetric] del: ereal_max)
lemma top_neq_ennreal[simp]: "top \<noteq> ennreal r"
using ennreal_neq_top[of r] by (auto simp del: ennreal_neq_top)
lemma ennreal_less_top[simp]: "ennreal x < top"
by transfer (simp add: top_ereal_def max_def)
lemma ennreal_neg: "x \<le> 0 \<Longrightarrow> ennreal x = 0"
by transfer (simp add: max.absorb1)
lemma ennreal_inj[simp]:
"0 \<le> a \<Longrightarrow> 0 \<le> b \<Longrightarrow> ennreal a = ennreal b \<longleftrightarrow> a = b"
by (transfer fixing: a b) (auto simp: max_absorb2)
lemma ennreal_le_iff[simp]: "0 \<le> y \<Longrightarrow> ennreal x \<le> ennreal y \<longleftrightarrow> x \<le> y"
by (auto simp: ennreal_def zero_ereal_def less_eq_ennreal.abs_eq eq_onp_def split: split_max)
lemma le_ennreal_iff: "0 \<le> r \<Longrightarrow> x \<le> ennreal r \<longleftrightarrow> (\<exists>q\<ge>0. x = ennreal q \<and> q \<le> r)"
by (cases x) (auto simp: top_unique)
lemma ennreal_less_iff: "0 \<le> r \<Longrightarrow> ennreal r < ennreal q \<longleftrightarrow> r < q"
unfolding not_le[symmetric] by auto
lemma ennreal_eq_zero_iff[simp]: "0 \<le> x \<Longrightarrow> ennreal x = 0 \<longleftrightarrow> x = 0"
by transfer (auto simp: max_absorb2)
lemma ennreal_less_zero_iff[simp]: "0 < ennreal x \<longleftrightarrow> 0 < x"
by transfer (auto simp: max_def)
lemma ennreal_lessI: "0 < q \<Longrightarrow> r < q \<Longrightarrow> ennreal r < ennreal q"
by (cases "0 \<le> r") (auto simp: ennreal_less_iff ennreal_neg)
lemma ennreal_leI: "x \<le> y \<Longrightarrow> ennreal x \<le> ennreal y"
by (cases "0 \<le> y") (auto simp: ennreal_neg)
lemma enn2ereal_ennreal[simp]: "0 \<le> x \<Longrightarrow> enn2ereal (ennreal x) = x"
by transfer (simp add: max_absorb2)
lemma e2ennreal_enn2ereal[simp]: "e2ennreal (enn2ereal x) = x"
by (simp add: e2ennreal_def max_absorb2 ennreal.enn2ereal_inverse)
lemma enn2ereal_e2ennreal: "x \<ge> 0 \<Longrightarrow> enn2ereal (e2ennreal x) = x"
by (metis e2ennreal_enn2ereal ereal_ennreal_cases not_le)
lemma e2ennreal_ereal [simp]: "e2ennreal (ereal x) = ennreal x"
by (metis e2ennreal_def enn2ereal_inverse ennreal.rep_eq sup_ereal_def)
lemma ennreal_0[simp]: "ennreal 0 = 0"
by (simp add: ennreal_def max.absorb1 zero_ennreal.abs_eq)
lemma ennreal_1[simp]: "ennreal 1 = 1"
by transfer (simp add: max_absorb2)
lemma ennreal_eq_0_iff: "ennreal x = 0 \<longleftrightarrow> x \<le> 0"
by (cases "0 \<le> x") (auto simp: ennreal_neg)
lemma ennreal_le_iff2: "ennreal x \<le> ennreal y \<longleftrightarrow> ((0 \<le> y \<and> x \<le> y) \<or> (x \<le> 0 \<and> y \<le> 0))"
by (cases "0 \<le> y") (auto simp: ennreal_eq_0_iff ennreal_neg)
lemma ennreal_eq_1[simp]: "ennreal x = 1 \<longleftrightarrow> x = 1"
by (cases "0 \<le> x")
(auto simp: ennreal_neg ennreal_1[symmetric] simp del: ennreal_1)
lemma ennreal_le_1[simp]: "ennreal x \<le> 1 \<longleftrightarrow> x \<le> 1"
by (cases "0 \<le> x")
(auto simp: ennreal_neg ennreal_1[symmetric] simp del: ennreal_1)
lemma ennreal_ge_1[simp]: "ennreal x \<ge> 1 \<longleftrightarrow> x \<ge> 1"
by (cases "0 \<le> x")
(auto simp: ennreal_neg ennreal_1[symmetric] simp del: ennreal_1)
lemma one_less_ennreal[simp]: "1 < ennreal x \<longleftrightarrow> 1 < x"
by transfer (auto simp: max.absorb2 less_max_iff_disj)
lemma ennreal_plus[simp]:
"0 \<le> a \<Longrightarrow> 0 \<le> b \<Longrightarrow> ennreal (a + b) = ennreal a + ennreal b"
by (transfer fixing: a b) (auto simp: max_absorb2)
lemma sum_ennreal[simp]: "(\<And>i. i \<in> I \<Longrightarrow> 0 \<le> f i) \<Longrightarrow> (\<Sum>i\<in>I. ennreal (f i)) = ennreal (sum f I)"
by (induction I rule: infinite_finite_induct) (auto simp: sum_nonneg)
lemma sum_list_ennreal[simp]:
assumes "\<And>x. x \<in> set xs \<Longrightarrow> f x \<ge> 0"
shows "sum_list (map (\<lambda>x. ennreal (f x)) xs) = ennreal (sum_list (map f xs))"
using assms
proof (induction xs)
case (Cons x xs)
from Cons have "(\<Sum>x\<leftarrow>x # xs. ennreal (f x)) = ennreal (f x) + ennreal (sum_list (map f xs))"
by simp
also from Cons.prems have "\<dots> = ennreal (f x + sum_list (map f xs))"
by (intro ennreal_plus [symmetric] sum_list_nonneg) auto
finally show ?case by simp
qed simp_all
lemma ennreal_of_nat_eq_real_of_nat: "of_nat i = ennreal (of_nat i)"
by (induction i) simp_all
lemma of_nat_le_ennreal_iff[simp]: "0 \<le> r \<Longrightarrow> of_nat i \<le> ennreal r \<longleftrightarrow> of_nat i \<le> r"
by (simp add: ennreal_of_nat_eq_real_of_nat)
lemma ennreal_le_of_nat_iff[simp]: "ennreal r \<le> of_nat i \<longleftrightarrow> r \<le> of_nat i"
by (simp add: ennreal_of_nat_eq_real_of_nat)
lemma ennreal_indicator: "ennreal (indicator A x) = indicator A x"
by (auto split: split_indicator)
lemma ennreal_numeral[simp]: "ennreal (numeral n) = numeral n"
using ennreal_of_nat_eq_real_of_nat[of "numeral n"] by simp
lemma min_ennreal: "0 \<le> x \<Longrightarrow> 0 \<le> y \<Longrightarrow> min (ennreal x) (ennreal y) = ennreal (min x y)"
by (auto split: split_min)
lemma ennreal_half[simp]: "ennreal (1/2) = inverse 2"
by transfer (simp add: max.absorb2)
lemma ennreal_minus: "0 \<le> q \<Longrightarrow> ennreal r - ennreal q = ennreal (r - q)"
by transfer
(simp add: max.absorb2 zero_ereal_def ereal_max[symmetric] del: ereal_max)
lemma ennreal_minus_top[simp]: "ennreal a - top = 0"
by (simp add: minus_top_ennreal)
lemma e2eenreal_enn2ereal_diff [simp]:
"e2ennreal(enn2ereal x - enn2ereal y) = x - y" for x y
by (cases x, cases y, auto simp add: ennreal_minus e2ennreal_neg)
lemma ennreal_mult: "0 \<le> a \<Longrightarrow> 0 \<le> b \<Longrightarrow> ennreal (a * b) = ennreal a * ennreal b"
by transfer (simp add: max_absorb2)
lemma ennreal_mult': "0 \<le> a \<Longrightarrow> ennreal (a * b) = ennreal a * ennreal b"
by (cases "0 \<le> b") (auto simp: ennreal_mult ennreal_neg mult_nonneg_nonpos)
lemma indicator_mult_ennreal: "indicator A x * ennreal r = ennreal (indicator A x * r)"
by (simp split: split_indicator)
lemma ennreal_mult'': "0 \<le> b \<Longrightarrow> ennreal (a * b) = ennreal a * ennreal b"
by (cases "0 \<le> a") (auto simp: ennreal_mult ennreal_neg mult_nonpos_nonneg)
lemma numeral_mult_ennreal: "0 \<le> x \<Longrightarrow> numeral b * ennreal x = ennreal (numeral b * x)"
by (simp add: ennreal_mult)
lemma ennreal_power: "0 \<le> r \<Longrightarrow> ennreal r ^ n = ennreal (r ^ n)"
by (induction n) (auto simp: ennreal_mult)
lemma power_eq_top_ennreal: "x ^ n = top \<longleftrightarrow> (n \<noteq> 0 \<and> (x::ennreal) = top)"
by (cases x rule: ennreal_cases)
(auto simp: ennreal_power top_power_ennreal)
lemma inverse_ennreal: "0 < r \<Longrightarrow> inverse (ennreal r) = ennreal (inverse r)"
by transfer (simp add: max.absorb2)
lemma divide_ennreal: "0 \<le> r \<Longrightarrow> 0 < q \<Longrightarrow> ennreal r / ennreal q = ennreal (r / q)"
by (simp add: divide_ennreal_def inverse_ennreal ennreal_mult[symmetric] inverse_eq_divide)
lemma ennreal_inverse_power: "inverse (x ^ n :: ennreal) = inverse x ^ n"
proof (cases x rule: ennreal_cases)
case top with power_eq_top_ennreal[of x n] show ?thesis
by (cases "n = 0") auto
next
case (real r) then show ?thesis
proof cases
assume "x = 0" then show ?thesis
using power_eq_top_ennreal[of top "n - 1"]
by (cases n) (auto simp: ennreal_top_mult)
next
assume "x \<noteq> 0"
with real have "0 < r" by auto
with real show ?thesis
by (induction n)
(auto simp add: ennreal_power ennreal_mult[symmetric] inverse_ennreal)
qed
qed
lemma ennreal_divide_numeral: "0 \<le> x \<Longrightarrow> ennreal x / numeral b = ennreal (x / numeral b)"
by (subst divide_ennreal[symmetric]) auto
lemma prod_ennreal: "(\<And>i. i \<in> A \<Longrightarrow> 0 \<le> f i) \<Longrightarrow> (\<Prod>i\<in>A. ennreal (f i)) = ennreal (prod f A)"
by (induction A rule: infinite_finite_induct)
(auto simp: ennreal_mult prod_nonneg)
lemma mult_right_ennreal_cancel: "a * ennreal c = b * ennreal c \<longleftrightarrow> (a = b \<or> c \<le> 0)"
apply (cases "0 \<le> c")
apply (cases a b rule: ennreal2_cases)
apply (auto simp: ennreal_mult[symmetric] ennreal_neg ennreal_top_mult)
done
lemma ennreal_le_epsilon:
"(\<And>e::real. y < top \<Longrightarrow> 0 < e \<Longrightarrow> x \<le> y + ennreal e) \<Longrightarrow> x \<le> y"
apply (cases y rule: ennreal_cases)
apply (cases x rule: ennreal_cases)
apply (auto simp del: ennreal_plus simp add: top_unique ennreal_plus[symmetric]
intro: zero_less_one field_le_epsilon)
done
lemma ennreal_rat_dense:
fixes x y :: ennreal
shows "x < y \<Longrightarrow> \<exists>r::rat. x < real_of_rat r \<and> real_of_rat r < y"
proof transfer
fix x y :: ereal assume xy: "0 \<le> x" "0 \<le> y" "x < y"
moreover
from ereal_dense3[OF \<open>x < y\<close>]
obtain r where r: "x < ereal (real_of_rat r)" "ereal (real_of_rat r) < y"
by auto
then have "0 \<le> r"
using le_less_trans[OF \<open>0 \<le> x\<close> \<open>x < ereal (real_of_rat r)\<close>] by auto
with r show "\<exists>r. x < (sup 0 \<circ> ereal) (real_of_rat r) \<and> (sup 0 \<circ> ereal) (real_of_rat r) < y"
by (intro exI[of _ r]) (auto simp: max_absorb2)
qed
lemma ennreal_Ex_less_of_nat: "(x::ennreal) < top \<Longrightarrow> \<exists>n. x < of_nat n"
by (cases x rule: ennreal_cases)
(auto simp: ennreal_of_nat_eq_real_of_nat ennreal_less_iff reals_Archimedean2)
subsection \<open>Coercion from @{typ ennreal} to @{typ real}\<close>
definition "enn2real x = real_of_ereal (enn2ereal x)"
lemma enn2real_nonneg[simp]: "0 \<le> enn2real x"
by (auto simp: enn2real_def intro!: real_of_ereal_pos enn2ereal_nonneg)
lemma enn2real_mono: "a \<le> b \<Longrightarrow> b < top \<Longrightarrow> enn2real a \<le> enn2real b"
by (auto simp add: enn2real_def less_eq_ennreal.rep_eq intro!: real_of_ereal_positive_mono enn2ereal_nonneg)
lemma enn2real_of_nat[simp]: "enn2real (of_nat n) = n"
by (auto simp: enn2real_def)
lemma enn2real_ennreal[simp]: "0 \<le> r \<Longrightarrow> enn2real (ennreal r) = r"
by (simp add: enn2real_def)
lemma ennreal_enn2real[simp]: "r < top \<Longrightarrow> ennreal (enn2real r) = r"
by (cases r rule: ennreal_cases) auto
lemma real_of_ereal_enn2ereal[simp]: "real_of_ereal (enn2ereal x) = enn2real x"
by (simp add: enn2real_def)
lemma enn2real_top[simp]: "enn2real top = 0"
unfolding enn2real_def top_ennreal.rep_eq top_ereal_def by simp
lemma enn2real_0[simp]: "enn2real 0 = 0"
unfolding enn2real_def zero_ennreal.rep_eq by simp
lemma enn2real_1[simp]: "enn2real 1 = 1"
unfolding enn2real_def one_ennreal.rep_eq by simp
lemma enn2real_numeral[simp]: "enn2real (numeral n) = (numeral n)"
unfolding enn2real_def by simp
lemma enn2real_mult: "enn2real (a * b) = enn2real a * enn2real b"
unfolding enn2real_def
by (simp del: real_of_ereal_enn2ereal add: times_ennreal.rep_eq)
lemma enn2real_leI: "0 \<le> B \<Longrightarrow> x \<le> ennreal B \<Longrightarrow> enn2real x \<le> B"
by (cases x rule: ennreal_cases) (auto simp: top_unique)
lemma enn2real_positive_iff: "0 < enn2real x \<longleftrightarrow> (0 < x \<and> x < top)"
by (cases x rule: ennreal_cases) auto
lemma enn2real_eq_1_iff[simp]: "enn2real x = 1 \<longleftrightarrow> x = 1"
by (cases x) auto
subsection \<open>Coercion from @{typ enat} to @{typ ennreal}\<close>
definition ennreal_of_enat :: "enat \<Rightarrow> ennreal"
where
"ennreal_of_enat n = (case n of \<infinity> \<Rightarrow> top | enat n \<Rightarrow> of_nat n)"
declare [[coercion ennreal_of_enat]]
declare [[coercion "of_nat :: nat \<Rightarrow> ennreal"]]
lemma ennreal_of_enat_infty[simp]: "ennreal_of_enat \<infinity> = \<infinity>"
by (simp add: ennreal_of_enat_def)
lemma ennreal_of_enat_enat[simp]: "ennreal_of_enat (enat n) = of_nat n"
by (simp add: ennreal_of_enat_def)
lemma ennreal_of_enat_0[simp]: "ennreal_of_enat 0 = 0"
using ennreal_of_enat_enat[of 0] unfolding enat_0 by simp
lemma ennreal_of_enat_1[simp]: "ennreal_of_enat 1 = 1"
using ennreal_of_enat_enat[of 1] unfolding enat_1 by simp
lemma ennreal_top_neq_of_nat[simp]: "(top::ennreal) \<noteq> of_nat i"
using ennreal_of_nat_neq_top[of i] by metis
lemma ennreal_of_enat_inj[simp]: "ennreal_of_enat i = ennreal_of_enat j \<longleftrightarrow> i = j"
by (cases i j rule: enat.exhaust[case_product enat.exhaust]) auto
lemma ennreal_of_enat_le_iff[simp]: "ennreal_of_enat m \<le> ennreal_of_enat n \<longleftrightarrow> m \<le> n"
by (auto simp: ennreal_of_enat_def top_unique split: enat.split)
lemma of_nat_less_ennreal_of_nat[simp]: "of_nat n \<le> ennreal_of_enat x \<longleftrightarrow> of_nat n \<le> x"
by (cases x) (auto simp: of_nat_eq_enat)
lemma ennreal_of_enat_Sup: "ennreal_of_enat (Sup X) = (SUP x:X. ennreal_of_enat x)"
proof -
have "ennreal_of_enat (Sup X) \<le> (SUP x : X. ennreal_of_enat x)"
unfolding Sup_enat_def
proof (clarsimp, intro conjI impI)
fix x assume "finite X" "X \<noteq> {}"
then show "ennreal_of_enat (Max X) \<le> (SUP x : X. ennreal_of_enat x)"
by (intro SUP_upper Max_in)
next
assume "infinite X" "X \<noteq> {}"
have "\<exists>y\<in>X. r < ennreal_of_enat y" if r: "r < top" for r
proof -
from ennreal_Ex_less_of_nat[OF r] guess n .. note n = this
have "\<not> (X \<subseteq> enat ` {.. n})"
using \<open>infinite X\<close> by (auto dest: finite_subset)
then obtain x where x: "x \<in> X" "x \<notin> enat ` {..n}"
by blast
then have "of_nat n \<le> x"
by (cases x) (auto simp: of_nat_eq_enat)
with x show ?thesis
by (auto intro!: bexI[of _ x] less_le_trans[OF n])
qed
then have "(SUP x : X. ennreal_of_enat x) = top"
by simp
then show "top \<le> (SUP x : X. ennreal_of_enat x)"
unfolding top_unique by simp
qed
then show ?thesis
by (auto intro!: antisym Sup_least intro: Sup_upper)
qed
lemma ennreal_of_enat_eSuc[simp]: "ennreal_of_enat (eSuc x) = 1 + ennreal_of_enat x"
by (cases x) (auto simp: eSuc_enat)
subsection \<open>Topology on @{typ ennreal}\<close>
lemma enn2ereal_Iio: "enn2ereal -` {..<a} = (if 0 \<le> a then {..< e2ennreal a} else {})"
using enn2ereal_nonneg
by (cases a rule: ereal_ennreal_cases)
(auto simp add: vimage_def set_eq_iff ennreal.enn2ereal_inverse less_ennreal.rep_eq e2ennreal_def max_absorb2
simp del: enn2ereal_nonneg
intro: le_less_trans less_imp_le)
lemma enn2ereal_Ioi: "enn2ereal -` {a <..} = (if 0 \<le> a then {e2ennreal a <..} else UNIV)"
by (cases a rule: ereal_ennreal_cases)
(auto simp add: vimage_def set_eq_iff ennreal.enn2ereal_inverse less_ennreal.rep_eq e2ennreal_def max_absorb2
intro: less_le_trans)
instantiation ennreal :: linear_continuum_topology
begin
definition open_ennreal :: "ennreal set \<Rightarrow> bool"
where "(open :: ennreal set \<Rightarrow> bool) = generate_topology (range lessThan \<union> range greaterThan)"
instance
proof
show "\<exists>a b::ennreal. a \<noteq> b"
using zero_neq_one by (intro exI)
show "\<And>x y::ennreal. x < y \<Longrightarrow> \<exists>z>x. z < y"
proof transfer
fix x y :: ereal assume "0 \<le> x" and *: "x < y"
moreover from dense[OF *] guess z ..
ultimately show "\<exists>z\<in>Collect ((\<le>) 0). x < z \<and> z < y"
by (intro bexI[of _ z]) auto
qed
qed (rule open_ennreal_def)
end
lemma continuous_on_e2ennreal: "continuous_on A e2ennreal"
proof (rule continuous_on_subset)
show "continuous_on ({0..} \<union> {..0}) e2ennreal"
proof (rule continuous_on_closed_Un)
show "continuous_on {0 ..} e2ennreal"
by (rule continuous_onI_mono)
(auto simp add: less_eq_ennreal.abs_eq eq_onp_def enn2ereal_range)
show "continuous_on {.. 0} e2ennreal"
by (subst continuous_on_cong[OF refl, of _ _ "\<lambda>_. 0"])
(auto simp add: e2ennreal_neg continuous_on_const)
qed auto
show "A \<subseteq> {0..} \<union> {..0::ereal}"
by auto
qed
lemma continuous_at_e2ennreal: "continuous (at x within A) e2ennreal"
by (rule continuous_on_imp_continuous_within[OF continuous_on_e2ennreal, of _ UNIV]) auto
lemma continuous_on_enn2ereal: "continuous_on UNIV enn2ereal"
by (rule continuous_on_generate_topology[OF open_generated_order])
(auto simp add: enn2ereal_Iio enn2ereal_Ioi)
lemma continuous_at_enn2ereal: "continuous (at x within A) enn2ereal"
by (rule continuous_on_imp_continuous_within[OF continuous_on_enn2ereal]) auto
lemma sup_continuous_e2ennreal[order_continuous_intros]:
assumes f: "sup_continuous f" shows "sup_continuous (\<lambda>x. e2ennreal (f x))"
apply (rule sup_continuous_compose[OF _ f])
apply (rule continuous_at_left_imp_sup_continuous)
apply (auto simp: mono_def e2ennreal_mono continuous_at_e2ennreal)
done
lemma sup_continuous_enn2ereal[order_continuous_intros]:
assumes f: "sup_continuous f" shows "sup_continuous (\<lambda>x. enn2ereal (f x))"
apply (rule sup_continuous_compose[OF _ f])
apply (rule continuous_at_left_imp_sup_continuous)
apply (simp_all add: mono_def less_eq_ennreal.rep_eq continuous_at_enn2ereal)
done
lemma sup_continuous_mult_left_ennreal':
fixes c :: "ennreal"
shows "sup_continuous (\<lambda>x. c * x)"
unfolding sup_continuous_def
by transfer (auto simp: SUP_ereal_mult_left max.absorb2 SUP_upper2)
lemma sup_continuous_mult_left_ennreal[order_continuous_intros]:
"sup_continuous f \<Longrightarrow> sup_continuous (\<lambda>x. c * f x :: ennreal)"
by (rule sup_continuous_compose[OF sup_continuous_mult_left_ennreal'])
lemma sup_continuous_mult_right_ennreal[order_continuous_intros]:
"sup_continuous f \<Longrightarrow> sup_continuous (\<lambda>x. f x * c :: ennreal)"
using sup_continuous_mult_left_ennreal[of f c] by (simp add: mult.commute)
lemma sup_continuous_divide_ennreal[order_continuous_intros]:
fixes f g :: "'a::complete_lattice \<Rightarrow> ennreal"
shows "sup_continuous f \<Longrightarrow> sup_continuous (\<lambda>x. f x / c)"
unfolding divide_ennreal_def by (rule sup_continuous_mult_right_ennreal)
lemma transfer_enn2ereal_continuous_on [transfer_rule]:
"rel_fun (=) (rel_fun (rel_fun (=) pcr_ennreal) (=)) continuous_on continuous_on"
proof -
have "continuous_on A f" if "continuous_on A (\<lambda>x. enn2ereal (f x))" for A and f :: "'a \<Rightarrow> ennreal"
using continuous_on_compose2[OF continuous_on_e2ennreal[of "{0..}"] that]
by (auto simp: ennreal.enn2ereal_inverse subset_eq e2ennreal_def max_absorb2)
moreover
have "continuous_on A (\<lambda>x. enn2ereal (f x))" if "continuous_on A f" for A and f :: "'a \<Rightarrow> ennreal"
using continuous_on_compose2[OF continuous_on_enn2ereal that] by auto
ultimately
show ?thesis
by (auto simp add: rel_fun_def ennreal.pcr_cr_eq cr_ennreal_def)
qed
lemma transfer_sup_continuous[transfer_rule]:
"(rel_fun (rel_fun (=) pcr_ennreal) (=)) sup_continuous sup_continuous"
proof (safe intro!: rel_funI dest!: rel_fun_eq_pcr_ennreal[THEN iffD1])
show "sup_continuous (enn2ereal \<circ> f) \<Longrightarrow> sup_continuous f" for f :: "'a \<Rightarrow> _"
using sup_continuous_e2ennreal[of "enn2ereal \<circ> f"] by simp
show "sup_continuous f \<Longrightarrow> sup_continuous (enn2ereal \<circ> f)" for f :: "'a \<Rightarrow> _"
using sup_continuous_enn2ereal[of f] by (simp add: comp_def)
qed
lemma continuous_on_ennreal[tendsto_intros]:
"continuous_on A f \<Longrightarrow> continuous_on A (\<lambda>x. ennreal (f x))"
by transfer (auto intro!: continuous_on_max continuous_on_const continuous_on_ereal)
lemma tendsto_ennrealD:
assumes lim: "((\<lambda>x. ennreal (f x)) \<longlongrightarrow> ennreal x) F"
assumes *: "\<forall>\<^sub>F x in F. 0 \<le> f x" and x: "0 \<le> x"
shows "(f \<longlongrightarrow> x) F"
using continuous_on_tendsto_compose[OF continuous_on_enn2ereal lim]
apply simp
apply (subst (asm) tendsto_cong)
using *
apply eventually_elim
apply (auto simp: max_absorb2 \<open>0 \<le> x\<close>)
done
lemma tendsto_ennreal_iff[simp]:
"\<forall>\<^sub>F x in F. 0 \<le> f x \<Longrightarrow> 0 \<le> x \<Longrightarrow> ((\<lambda>x. ennreal (f x)) \<longlongrightarrow> ennreal x) F \<longleftrightarrow> (f \<longlongrightarrow> x) F"
by (auto dest: tendsto_ennrealD)
(auto simp: ennreal_def
intro!: continuous_on_tendsto_compose[OF continuous_on_e2ennreal[of UNIV]] tendsto_max)
lemma tendsto_enn2ereal_iff[simp]: "((\<lambda>i. enn2ereal (f i)) \<longlongrightarrow> enn2ereal x) F \<longleftrightarrow> (f \<longlongrightarrow> x) F"
using continuous_on_enn2ereal[THEN continuous_on_tendsto_compose, of f x F]
continuous_on_e2ennreal[THEN continuous_on_tendsto_compose, of "\<lambda>x. enn2ereal (f x)" "enn2ereal x" F UNIV]
by auto
lemma continuous_on_add_ennreal:
fixes f g :: "'a::topological_space \<Rightarrow> ennreal"
shows "continuous_on A f \<Longrightarrow> continuous_on A g \<Longrightarrow> continuous_on A (\<lambda>x. f x + g x)"
by (transfer fixing: A) (auto intro!: tendsto_add_ereal_nonneg simp: continuous_on_def)
lemma continuous_on_inverse_ennreal[continuous_intros]:
fixes f :: "'a::topological_space \<Rightarrow> ennreal"
shows "continuous_on A f \<Longrightarrow> continuous_on A (\<lambda>x. inverse (f x))"
proof (transfer fixing: A)
show "pred_fun top ((\<le>) 0) f \<Longrightarrow> continuous_on A (\<lambda>x. inverse (f x))" if "continuous_on A f"
for f :: "'a \<Rightarrow> ereal"
using continuous_on_compose2[OF continuous_on_inverse_ereal that] by (auto simp: subset_eq)
qed
instance ennreal :: topological_comm_monoid_add
proof
show "((\<lambda>x. fst x + snd x) \<longlongrightarrow> a + b) (nhds a \<times>\<^sub>F nhds b)" for a b :: ennreal
using continuous_on_add_ennreal[of UNIV fst snd]
using tendsto_at_iff_tendsto_nhds[symmetric, of "\<lambda>x::(ennreal \<times> ennreal). fst x + snd x"]
by (auto simp: continuous_on_eq_continuous_at)
(simp add: isCont_def nhds_prod[symmetric])
qed
lemma sup_continuous_add_ennreal[order_continuous_intros]:
fixes f g :: "'a::complete_lattice \<Rightarrow> ennreal"
shows "sup_continuous f \<Longrightarrow> sup_continuous g \<Longrightarrow> sup_continuous (\<lambda>x. f x + g x)"
by transfer (auto intro!: sup_continuous_add)
lemma ennreal_suminf_lessD: "(\<Sum>i. f i :: ennreal) < x \<Longrightarrow> f i < x"
using le_less_trans[OF sum_le_suminf[OF summableI, of "{i}" f]] by simp
lemma sums_ennreal[simp]: "(\<And>i. 0 \<le> f i) \<Longrightarrow> 0 \<le> x \<Longrightarrow> (\<lambda>i. ennreal (f i)) sums ennreal x \<longleftrightarrow> f sums x"
unfolding sums_def by (simp add: always_eventually sum_nonneg)
lemma summable_suminf_not_top: "(\<And>i. 0 \<le> f i) \<Longrightarrow> (\<Sum>i. ennreal (f i)) \<noteq> top \<Longrightarrow> summable f"
using summable_sums[OF summableI, of "\<lambda>i. ennreal (f i)"]
by (cases "\<Sum>i. ennreal (f i)" rule: ennreal_cases)
(auto simp: summable_def)
lemma suminf_ennreal[simp]:
"(\<And>i. 0 \<le> f i) \<Longrightarrow> (\<Sum>i. ennreal (f i)) \<noteq> top \<Longrightarrow> (\<Sum>i. ennreal (f i)) = ennreal (\<Sum>i. f i)"
by (rule sums_unique[symmetric]) (simp add: summable_suminf_not_top suminf_nonneg summable_sums)
lemma sums_enn2ereal[simp]: "(\<lambda>i. enn2ereal (f i)) sums enn2ereal x \<longleftrightarrow> f sums x"
unfolding sums_def by (simp add: always_eventually sum_nonneg)
lemma suminf_enn2ereal[simp]: "(\<Sum>i. enn2ereal (f i)) = enn2ereal (suminf f)"
by (rule sums_unique[symmetric]) (simp add: summable_sums)
lemma transfer_e2ennreal_suminf [transfer_rule]: "rel_fun (rel_fun (=) pcr_ennreal) pcr_ennreal suminf suminf"
by (auto simp: rel_funI rel_fun_eq_pcr_ennreal comp_def)
lemma ennreal_suminf_cmult[simp]: "(\<Sum>i. r * f i) = r * (\<Sum>i. f i::ennreal)"
by transfer (auto intro!: suminf_cmult_ereal)
lemma ennreal_suminf_multc[simp]: "(\<Sum>i. f i * r) = (\<Sum>i. f i::ennreal) * r"
using ennreal_suminf_cmult[of r f] by (simp add: ac_simps)
lemma ennreal_suminf_divide[simp]: "(\<Sum>i. f i / r) = (\<Sum>i. f i::ennreal) / r"
by (simp add: divide_ennreal_def)
lemma ennreal_suminf_neq_top: "summable f \<Longrightarrow> (\<And>i. 0 \<le> f i) \<Longrightarrow> (\<Sum>i. ennreal (f i)) \<noteq> top"
using sums_ennreal[of f "suminf f"]
by (simp add: suminf_nonneg sums_unique[symmetric] summable_sums_iff[symmetric] del: sums_ennreal)
lemma suminf_ennreal_eq:
"(\<And>i. 0 \<le> f i) \<Longrightarrow> f sums x \<Longrightarrow> (\<Sum>i. ennreal (f i)) = ennreal x"
using suminf_nonneg[of f] sums_unique[of f x]
by (intro sums_unique[symmetric]) (auto simp: summable_sums_iff)
lemma ennreal_suminf_bound_add:
fixes f :: "nat \<Rightarrow> ennreal"
shows "(\<And>N. (\<Sum>n<N. f n) + y \<le> x) \<Longrightarrow> suminf f + y \<le> x"
by transfer (auto intro!: suminf_bound_add)
lemma ennreal_suminf_SUP_eq_directed:
fixes f :: "'a \<Rightarrow> nat \<Rightarrow> ennreal"
assumes *: "\<And>N i j. i \<in> I \<Longrightarrow> j \<in> I \<Longrightarrow> finite N \<Longrightarrow> \<exists>k\<in>I. \<forall>n\<in>N. f i n \<le> f k n \<and> f j n \<le> f k n"
shows "(\<Sum>n. SUP i:I. f i n) = (SUP i:I. \<Sum>n. f i n)"
proof cases
assume "I \<noteq> {}"
then obtain i where "i \<in> I" by auto
from * show ?thesis
by (transfer fixing: I)
(auto simp: max_absorb2 SUP_upper2[OF \<open>i \<in> I\<close>] suminf_nonneg summable_ereal_pos \<open>I \<noteq> {}\<close>
intro!: suminf_SUP_eq_directed)
qed (simp add: bot_ennreal)
lemma INF_ennreal_add_const:
fixes f g :: "nat \<Rightarrow> ennreal"
shows "(INF i. f i + c) = (INF i. f i) + c"
using continuous_at_Inf_mono[of "\<lambda>x. x + c" "f`UNIV"]
using continuous_add[of "at_right (Inf (range f))", of "\<lambda>x. x" "\<lambda>x. c"]
by (auto simp: mono_def)
lemma INF_ennreal_const_add:
fixes f g :: "nat \<Rightarrow> ennreal"
shows "(INF i. c + f i) = c + (INF i. f i)"
using INF_ennreal_add_const[of f c] by (simp add: ac_simps)
lemma SUP_mult_left_ennreal: "c * (SUP i:I. f i) = (SUP i:I. c * f i ::ennreal)"
proof cases
assume "I \<noteq> {}" then show ?thesis
by transfer (auto simp add: SUP_ereal_mult_left max_absorb2 SUP_upper2)
qed (simp add: bot_ennreal)
lemma SUP_mult_right_ennreal: "(SUP i:I. f i) * c = (SUP i:I. f i * c ::ennreal)"
using SUP_mult_left_ennreal by (simp add: mult.commute)
lemma SUP_divide_ennreal: "(SUP i:I. f i) / c = (SUP i:I. f i / c ::ennreal)"
using SUP_mult_right_ennreal by (simp add: divide_ennreal_def)
lemma ennreal_SUP_of_nat_eq_top: "(SUP x. of_nat x :: ennreal) = top"
proof (intro antisym top_greatest le_SUP_iff[THEN iffD2] allI impI)
fix y :: ennreal assume "y < top"
then obtain r where "y = ennreal r"
by (cases y rule: ennreal_cases) auto
then show "\<exists>i\<in>UNIV. y < of_nat i"
using reals_Archimedean2[of "max 1 r"] zero_less_one
by (simp add: ennreal_Ex_less_of_nat)
qed
lemma ennreal_SUP_eq_top:
fixes f :: "'a \<Rightarrow> ennreal"
assumes "\<And>n. \<exists>i\<in>I. of_nat n \<le> f i"
shows "(SUP i : I. f i) = top"
proof -
have "(SUP x. of_nat x :: ennreal) \<le> (SUP i : I. f i)"
using assms by (auto intro!: SUP_least intro: SUP_upper2)
then show ?thesis
by (auto simp: ennreal_SUP_of_nat_eq_top top_unique)
qed
lemma ennreal_INF_const_minus:
fixes f :: "'a \<Rightarrow> ennreal"
shows "I \<noteq> {} \<Longrightarrow> (SUP x:I. c - f x) = c - (INF x:I. f x)"
by (transfer fixing: I)
(simp add: sup_max[symmetric] SUP_sup_const1 SUP_ereal_minus_right del: sup_ereal_def)
lemma of_nat_Sup_ennreal:
assumes "A \<noteq> {}" "bdd_above A"
shows "of_nat (Sup A) = (SUP a:A. of_nat a :: ennreal)"
proof (intro antisym)
show "(SUP a:A. of_nat a::ennreal) \<le> of_nat (Sup A)"
by (intro SUP_least of_nat_mono) (auto intro: cSup_upper assms)
have "Sup A \<in> A"
unfolding Sup_nat_def using assms by (intro Max_in) (auto simp: bdd_above_nat)
then show "of_nat (Sup A) \<le> (SUP a:A. of_nat a::ennreal)"
by (intro SUP_upper)
qed
lemma ennreal_tendsto_const_minus:
fixes g :: "'a \<Rightarrow> ennreal"
assumes ae: "\<forall>\<^sub>F x in F. g x \<le> c"
assumes g: "((\<lambda>x. c - g x) \<longlongrightarrow> 0) F"
shows "(g \<longlongrightarrow> c) F"
proof (cases c rule: ennreal_cases)
case top with tendsto_unique[OF _ g, of "top"] show ?thesis
by (cases "F = bot") auto
next
case (real r)
then have "\<forall>x. \<exists>q\<ge>0. g x \<le> c \<longrightarrow> (g x = ennreal q \<and> q \<le> r)"
by (auto simp: le_ennreal_iff)
then obtain f where *: "0 \<le> f x" "g x = ennreal (f x)" "f x \<le> r" if "g x \<le> c" for x
by metis
from ae have ae2: "\<forall>\<^sub>F x in F. c - g x = ennreal (r - f x) \<and> f x \<le> r \<and> g x = ennreal (f x) \<and> 0 \<le> f x"
proof eventually_elim
fix x assume "g x \<le> c" with *[of x] \<open>0 \<le> r\<close> show "c - g x = ennreal (r - f x) \<and> f x \<le> r \<and> g x = ennreal (f x) \<and> 0 \<le> f x"
by (auto simp: real ennreal_minus)
qed
with g have "((\<lambda>x. ennreal (r - f x)) \<longlongrightarrow> ennreal 0) F"
by (auto simp add: tendsto_cong eventually_conj_iff)
with ae2 have "((\<lambda>x. r - f x) \<longlongrightarrow> 0) F"
by (subst (asm) tendsto_ennreal_iff) (auto elim: eventually_mono)
then have "(f \<longlongrightarrow> r) F"
by (rule Lim_transform2[OF tendsto_const])
with ae2 have "((\<lambda>x. ennreal (f x)) \<longlongrightarrow> ennreal r) F"
by (subst tendsto_ennreal_iff) (auto elim: eventually_mono simp: real)
with ae2 show ?thesis
by (auto simp: real tendsto_cong eventually_conj_iff)
qed
lemma ennreal_SUP_add:
fixes f g :: "nat \<Rightarrow> ennreal"
shows "incseq f \<Longrightarrow> incseq g \<Longrightarrow> (SUP i. f i + g i) = SUPREMUM UNIV f + SUPREMUM UNIV g"
unfolding incseq_def le_fun_def
by transfer
(simp add: SUP_ereal_add incseq_def le_fun_def max_absorb2 SUP_upper2)
lemma ennreal_SUP_sum:
fixes f :: "'a \<Rightarrow> nat \<Rightarrow> ennreal"
shows "(\<And>i. i \<in> I \<Longrightarrow> incseq (f i)) \<Longrightarrow> (SUP n. \<Sum>i\<in>I. f i n) = (\<Sum>i\<in>I. SUP n. f i n)"
unfolding incseq_def
by transfer
(simp add: SUP_ereal_sum incseq_def SUP_upper2 max_absorb2 sum_nonneg)
lemma ennreal_liminf_minus:
fixes f :: "nat \<Rightarrow> ennreal"
shows "(\<And>n. f n \<le> c) \<Longrightarrow> liminf (\<lambda>n. c - f n) = c - limsup f"
apply transfer
apply (simp add: ereal_diff_positive max.absorb2 liminf_ereal_cminus)
apply (subst max.absorb2)
apply (rule ereal_diff_positive)
apply (rule Limsup_bounded)
apply auto
done
lemma ennreal_continuous_on_cmult:
"(c::ennreal) < top \<Longrightarrow> continuous_on A f \<Longrightarrow> continuous_on A (\<lambda>x. c * f x)"
by (transfer fixing: A) (auto intro: continuous_on_cmult_ereal)
lemma ennreal_tendsto_cmult:
"(c::ennreal) < top \<Longrightarrow> (f \<longlongrightarrow> x) F \<Longrightarrow> ((\<lambda>x. c * f x) \<longlongrightarrow> c * x) F"
by (rule continuous_on_tendsto_compose[where g=f, OF ennreal_continuous_on_cmult, where s=UNIV])
(auto simp: continuous_on_id)
lemma tendsto_ennrealI[intro, simp]:
"(f \<longlongrightarrow> x) F \<Longrightarrow> ((\<lambda>x. ennreal (f x)) \<longlongrightarrow> ennreal x) F"
by (auto simp: ennreal_def
intro!: continuous_on_tendsto_compose[OF continuous_on_e2ennreal[of UNIV]] tendsto_max)
lemma ennreal_suminf_minus:
fixes f g :: "nat \<Rightarrow> ennreal"
shows "(\<And>i. g i \<le> f i) \<Longrightarrow> suminf f \<noteq> top \<Longrightarrow> suminf g \<noteq> top \<Longrightarrow> (\<Sum>i. f i - g i) = suminf f - suminf g"
by transfer
(auto simp add: max.absorb2 ereal_diff_positive suminf_le_pos top_ereal_def intro!: suminf_ereal_minus)
lemma ennreal_Sup_countable_SUP:
"A \<noteq> {} \<Longrightarrow> \<exists>f::nat \<Rightarrow> ennreal. incseq f \<and> range f \<subseteq> A \<and> Sup A = (SUP i. f i)"
unfolding incseq_def
apply transfer
subgoal for A
using Sup_countable_SUP[of A]
apply (clarsimp simp add: incseq_def[symmetric] SUP_upper2 max.absorb2 image_subset_iff Sup_upper2 cong: conj_cong)
subgoal for f
by (intro exI[of _ f]) auto
done
done
lemma ennreal_Inf_countable_INF:
"A \<noteq> {} \<Longrightarrow> \<exists>f::nat \<Rightarrow> ennreal. decseq f \<and> range f \<subseteq> A \<and> Inf A = (INF i. f i)"
including ennreal.lifting
unfolding decseq_def
apply transfer
subgoal for A
using Inf_countable_INF[of A]
apply (clarsimp simp add: decseq_def[symmetric])
subgoal for f
by (intro exI[of _ f]) auto
done
done
lemma ennreal_SUP_countable_SUP:
"A \<noteq> {} \<Longrightarrow> \<exists>f::nat \<Rightarrow> ennreal. range f \<subseteq> g`A \<and> SUPREMUM A g = SUPREMUM UNIV f"
using ennreal_Sup_countable_SUP [of "g`A"] by auto
lemma of_nat_tendsto_top_ennreal: "(\<lambda>n::nat. of_nat n :: ennreal) \<longlonglongrightarrow> top"
using LIMSEQ_SUP[of "of_nat :: nat \<Rightarrow> ennreal"]
by (simp add: ennreal_SUP_of_nat_eq_top incseq_def)
lemma SUP_sup_continuous_ennreal:
fixes f :: "ennreal \<Rightarrow> 'a::complete_lattice"
assumes f: "sup_continuous f" and "I \<noteq> {}"
shows "(SUP i:I. f (g i)) = f (SUP i:I. g i)"
proof (rule antisym)
show "(SUP i:I. f (g i)) \<le> f (SUP i:I. g i)"
by (rule mono_SUP[OF sup_continuous_mono[OF f]])
from ennreal_Sup_countable_SUP[of "g`I"] \<open>I \<noteq> {}\<close>
obtain M :: "nat \<Rightarrow> ennreal" where "incseq M" and M: "range M \<subseteq> g ` I" and eq: "(SUP i : I. g i) = (SUP i. M i)"
by auto
have "f (SUP i : I. g i) = (SUP i : range M. f i)"
unfolding eq sup_continuousD[OF f \<open>mono M\<close>] by simp
also have "\<dots> \<le> (SUP i : I. f (g i))"
by (insert M, drule SUP_subset_mono) auto
finally show "f (SUP i : I. g i) \<le> (SUP i : I. f (g i))" .
qed
lemma ennreal_suminf_SUP_eq:
fixes f :: "nat \<Rightarrow> nat \<Rightarrow> ennreal"
shows "(\<And>i. incseq (\<lambda>n. f n i)) \<Longrightarrow> (\<Sum>i. SUP n. f n i) = (SUP n. \<Sum>i. f n i)"
apply (rule ennreal_suminf_SUP_eq_directed)
subgoal for N n j
by (auto simp: incseq_def intro!:exI[of _ "max n j"])
done
lemma ennreal_SUP_add_left:
fixes c :: ennreal
shows "I \<noteq> {} \<Longrightarrow> (SUP i:I. f i + c) = (SUP i:I. f i) + c"
apply transfer
apply (simp add: SUP_ereal_add_left)
apply (subst (1 2) max.absorb2)
apply (auto intro: SUP_upper2 ereal_add_nonneg_nonneg)
done
lemma ennreal_SUP_const_minus: (* TODO: rename: ennreal_SUP_const_minus *)
fixes f :: "'a \<Rightarrow> ennreal"
shows "I \<noteq> {} \<Longrightarrow> c < top \<Longrightarrow> (INF x:I. c - f x) = c - (SUP x:I. f x)"
apply (transfer fixing: I)
unfolding ex_in_conv[symmetric]
apply (auto simp add: sup_max[symmetric] SUP_upper2 sup_absorb2
simp del: sup_ereal_def)
apply (subst INF_ereal_minus_right[symmetric])
apply (auto simp del: sup_ereal_def simp add: sup_INF)
done
subsection \<open>Approximation lemmas\<close>
lemma INF_approx_ennreal:
fixes x::ennreal and e::real
assumes "e > 0"
assumes INF: "x = (INF i : A. f i)"
assumes "x \<noteq> \<infinity>"
shows "\<exists>i \<in> A. f i < x + e"
proof -
have "(INF i : A. f i) < x + e"
unfolding INF[symmetric] using \<open>0<e\<close> \<open>x \<noteq> \<infinity>\<close> by (cases x) auto
then show ?thesis
unfolding INF_less_iff .
qed
lemma SUP_approx_ennreal:
fixes x::ennreal and e::real
assumes "e > 0" "A \<noteq> {}"
assumes SUP: "x = (SUP i : A. f i)"
assumes "x \<noteq> \<infinity>"
shows "\<exists>i \<in> A. x < f i + e"
proof -
have "x < x + e"
using \<open>0<e\<close> \<open>x \<noteq> \<infinity>\<close> by (cases x) auto
also have "x + e = (SUP i : A. f i + e)"
unfolding SUP ennreal_SUP_add_left[OF \<open>A \<noteq> {}\<close>] ..
finally show ?thesis
unfolding less_SUP_iff .
qed
lemma ennreal_approx_SUP:
fixes x::ennreal
assumes f_bound: "\<And>i. i \<in> A \<Longrightarrow> f i \<le> x"
assumes approx: "\<And>e. (e::real) > 0 \<Longrightarrow> \<exists>i \<in> A. x \<le> f i + e"
shows "x = (SUP i : A. f i)"
proof (rule antisym)
show "x \<le> (SUP i:A. f i)"
proof (rule ennreal_le_epsilon)
fix e :: real assume "0 < e"
from approx[OF this] guess i ..
then have "x \<le> f i + e"
by simp
also have "\<dots> \<le> (SUP i:A. f i) + e"
by (intro add_mono \<open>i \<in> A\<close> SUP_upper order_refl)
finally show "x \<le> (SUP i:A. f i) + e" .
qed
qed (intro SUP_least f_bound)
lemma ennreal_approx_INF:
fixes x::ennreal
assumes f_bound: "\<And>i. i \<in> A \<Longrightarrow> x \<le> f i"
assumes approx: "\<And>e. (e::real) > 0 \<Longrightarrow> \<exists>i \<in> A. f i \<le> x + e"
shows "x = (INF i : A. f i)"
proof (rule antisym)
show "(INF i:A. f i) \<le> x"
proof (rule ennreal_le_epsilon)
fix e :: real assume "0 < e"
from approx[OF this] guess i .. note i = this
then have "(INF i:A. f i) \<le> f i"
by (intro INF_lower)
also have "\<dots> \<le> x + e"
by fact
finally show "(INF i:A. f i) \<le> x + e" .
qed
qed (intro INF_greatest f_bound)
lemma ennreal_approx_unit:
"(\<And>a::ennreal. 0 < a \<Longrightarrow> a < 1 \<Longrightarrow> a * z \<le> y) \<Longrightarrow> z \<le> y"
apply (subst SUP_mult_right_ennreal[of "\<lambda>x. x" "{0 <..< 1}" z, simplified])
apply (rule SUP_least)
apply auto
done
lemma suminf_ennreal2:
"(\<And>i. 0 \<le> f i) \<Longrightarrow> summable f \<Longrightarrow> (\<Sum>i. ennreal (f i)) = ennreal (\<Sum>i. f i)"
using suminf_ennreal_eq by blast
lemma less_top_ennreal: "x < top \<longleftrightarrow> (\<exists>r\<ge>0. x = ennreal r)"
by (cases x) auto
lemma tendsto_top_iff_ennreal:
fixes f :: "'a \<Rightarrow> ennreal"
shows "(f \<longlongrightarrow> top) F \<longleftrightarrow> (\<forall>l\<ge>0. eventually (\<lambda>x. ennreal l < f x) F)"
by (auto simp: less_top_ennreal order_tendsto_iff )
lemma ennreal_tendsto_top_eq_at_top:
"((\<lambda>z. ennreal (f z)) \<longlongrightarrow> top) F \<longleftrightarrow> (LIM z F. f z :> at_top)"
unfolding filterlim_at_top_dense tendsto_top_iff_ennreal
apply (auto simp: ennreal_less_iff)
subgoal for y
by (auto elim!: eventually_mono allE[of _ "max 0 y"])
done
lemma tendsto_0_if_Limsup_eq_0_ennreal:
fixes f :: "_ \<Rightarrow> ennreal"
shows "Limsup F f = 0 \<Longrightarrow> (f \<longlongrightarrow> 0) F"
using Liminf_le_Limsup[of F f] tendsto_iff_Liminf_eq_Limsup[of F f 0]
by (cases "F = bot") auto
lemma diff_le_self_ennreal[simp]: "a - b \<le> (a::ennreal)"
by (cases a b rule: ennreal2_cases) (auto simp: ennreal_minus)
lemma ennreal_ineq_diff_add: "b \<le> a \<Longrightarrow> a = b + (a - b::ennreal)"
by transfer (auto simp: ereal_diff_positive max.absorb2 ereal_ineq_diff_add)
lemma ennreal_mult_strict_left_mono: "(a::ennreal) < c \<Longrightarrow> 0 < b \<Longrightarrow> b < top \<Longrightarrow> b * a < b * c"
by transfer (auto intro!: ereal_mult_strict_left_mono)
lemma ennreal_between: "0 < e \<Longrightarrow> 0 < x \<Longrightarrow> x < top \<Longrightarrow> x - e < (x::ennreal)"
by transfer (auto intro!: ereal_between)
lemma minus_less_iff_ennreal: "b < top \<Longrightarrow> b \<le> a \<Longrightarrow> a - b < c \<longleftrightarrow> a < c + (b::ennreal)"
by transfer
(auto simp: top_ereal_def ereal_minus_less le_less)
lemma tendsto_zero_ennreal:
assumes ev: "\<And>r. 0 < r \<Longrightarrow> \<forall>\<^sub>F x in F. f x < ennreal r"
shows "(f \<longlongrightarrow> 0) F"
proof (rule order_tendstoI)
fix e::ennreal assume "e > 0"
obtain e'::real where "e' > 0" "ennreal e' < e"
using \<open>0 < e\<close> dense[of 0 "if e = top then 1 else (enn2real e)"]
by (cases e) (auto simp: ennreal_less_iff)
from ev[OF \<open>e' > 0\<close>] show "\<forall>\<^sub>F x in F. f x < e"
by eventually_elim (insert \<open>ennreal e' < e\<close>, auto)
qed simp
lifting_update ennreal.lifting
lifting_forget ennreal.lifting
subsection \<open>@{typ ennreal} theorems\<close>
lemma neq_top_trans: fixes x y :: ennreal shows "\<lbrakk> y \<noteq> top; x \<le> y \<rbrakk> \<Longrightarrow> x \<noteq> top"
by (auto simp: top_unique)
lemma diff_diff_ennreal: fixes a b :: ennreal shows "a \<le> b \<Longrightarrow> b \<noteq> \<infinity> \<Longrightarrow> b - (b - a) = a"
by (cases a b rule: ennreal2_cases)
(auto simp: ennreal_minus top_unique)
lemma ennreal_less_one_iff[simp]: "ennreal x < 1 \<longleftrightarrow> x < 1"
by (cases "0 \<le> x")
(auto simp: ennreal_neg ennreal_1[symmetric] ennreal_less_iff simp del: ennreal_1)
lemma SUP_const_minus_ennreal:
fixes f :: "'a \<Rightarrow> ennreal" shows "I \<noteq> {} \<Longrightarrow> (SUP x:I. c - f x) = c - (INF x:I. f x)"
including ennreal.lifting
by (transfer fixing: I)
(simp add: sup_ereal_def[symmetric] SUP_sup_distrib[symmetric] SUP_ereal_minus_right
del: sup_ereal_def)
lemma zero_minus_ennreal[simp]: "0 - (a::ennreal) = 0"
including ennreal.lifting
by transfer (simp split: split_max)
lemma diff_diff_commute_ennreal:
fixes a b c :: ennreal shows "a - b - c = a - c - b"
by (cases a b c rule: ennreal3_cases) (simp_all add: ennreal_minus field_simps)
lemma diff_gr0_ennreal: "b < (a::ennreal) \<Longrightarrow> 0 < a - b"
including ennreal.lifting by transfer (auto simp: ereal_diff_gr0 ereal_diff_positive split: split_max)
lemma divide_le_posI_ennreal:
fixes x y z :: ennreal
shows "x > 0 \<Longrightarrow> z \<le> x * y \<Longrightarrow> z / x \<le> y"
by (cases x y z rule: ennreal3_cases)
(auto simp: divide_ennreal ennreal_mult[symmetric] field_simps top_unique)
lemma add_diff_eq_ennreal:
fixes x y z :: ennreal
shows "z \<le> y \<Longrightarrow> x + (y - z) = x + y - z"
including ennreal.lifting
by transfer
(insert ereal_add_mono[of 0], auto simp add: ereal_diff_positive max.absorb2 add_diff_eq_ereal)
lemma add_diff_inverse_ennreal:
fixes x y :: ennreal shows "x \<le> y \<Longrightarrow> x + (y - x) = y"
by (cases x) (simp_all add: top_unique add_diff_eq_ennreal)
lemma add_diff_eq_iff_ennreal[simp]:
fixes x y :: ennreal shows "x + (y - x) = y \<longleftrightarrow> x \<le> y"
proof
assume *: "x + (y - x) = y" show "x \<le> y"
by (subst *[symmetric]) simp
qed (simp add: add_diff_inverse_ennreal)
lemma add_diff_le_ennreal: "a + b - c \<le> a + (b - c::ennreal)"
apply (cases a b c rule: ennreal3_cases)
subgoal for a' b' c'
by (cases "0 \<le> b' - c'")
(simp_all add: ennreal_minus ennreal_plus[symmetric] top_add ennreal_neg
del: ennreal_plus)
apply (simp_all add: top_add ennreal_plus[symmetric] del: ennreal_plus)
done
lemma diff_eq_0_ennreal: "a < top \<Longrightarrow> a \<le> b \<Longrightarrow> a - b = (0::ennreal)"
using ennreal_minus_pos_iff gr_zeroI not_less by blast
lemma diff_diff_ennreal': fixes x y z :: ennreal shows "z \<le> y \<Longrightarrow> y - z \<le> x \<Longrightarrow> x - (y - z) = x + z - y"
by (cases x; cases y; cases z)
(auto simp add: top_add add_top minus_top_ennreal ennreal_minus ennreal_plus[symmetric] top_unique
simp del: ennreal_plus)
lemma diff_diff_ennreal'': fixes x y z :: ennreal
shows "z \<le> y \<Longrightarrow> x - (y - z) = (if y - z \<le> x then x + z - y else 0)"
by (cases x; cases y; cases z)
(auto simp add: top_add add_top minus_top_ennreal ennreal_minus ennreal_plus[symmetric] top_unique ennreal_neg
simp del: ennreal_plus)
lemma power_less_top_ennreal: fixes x :: ennreal shows "x ^ n < top \<longleftrightarrow> x < top \<or> n = 0"
using power_eq_top_ennreal[of x n] by (auto simp: less_top)
lemma ennreal_divide_times: "(a / b) * c = a * (c / b :: ennreal)"
by (simp add: mult.commute ennreal_times_divide)
lemma diff_less_top_ennreal: "a - b < top \<longleftrightarrow> a < (top :: ennreal)"
by (cases a; cases b) (auto simp: ennreal_minus)
lemma divide_less_ennreal: "b \<noteq> 0 \<Longrightarrow> b < top \<Longrightarrow> a / b < c \<longleftrightarrow> a < (c * b :: ennreal)"
by (cases a; cases b; cases c)
(auto simp: divide_ennreal ennreal_mult[symmetric] ennreal_less_iff field_simps ennreal_top_mult ennreal_top_divide)
lemma one_less_numeral[simp]: "1 < (numeral n::ennreal) \<longleftrightarrow> (num.One < n)"
by (simp del: ennreal_1 ennreal_numeral add: ennreal_1[symmetric] ennreal_numeral[symmetric] ennreal_less_iff)
lemma divide_eq_1_ennreal: "a / b = (1::ennreal) \<longleftrightarrow> (b \<noteq> top \<and> b \<noteq> 0 \<and> b = a)"
by (cases a ; cases b; cases "b = 0") (auto simp: ennreal_top_divide divide_ennreal split: if_split_asm)
lemma ennreal_mult_cancel_left: "(a * b = a * c) = (a = top \<and> b \<noteq> 0 \<and> c \<noteq> 0 \<or> a = 0 \<or> b = (c::ennreal))"
by (cases a; cases b; cases c) (auto simp: ennreal_mult[symmetric] ennreal_mult_top ennreal_top_mult)
lemma ennreal_minus_if: "ennreal a - ennreal b = ennreal (if 0 \<le> b then (if b \<le> a then a - b else 0) else a)"
by (auto simp: ennreal_minus ennreal_neg)
lemma ennreal_plus_if: "ennreal a + ennreal b = ennreal (if 0 \<le> a then (if 0 \<le> b then a + b else a) else b)"
by (auto simp: ennreal_neg)
lemma power_le_one_iff: "0 \<le> (a::real) \<Longrightarrow> a ^ n \<le> 1 \<longleftrightarrow> (n = 0 \<or> a \<le> 1)"
by (metis (mono_tags, hide_lams) le_less neq0_conv not_le one_le_power power_0 power_eq_imp_eq_base power_le_one zero_le_one)
lemma ennreal_diff_le_mono_left: "a \<le> b \<Longrightarrow> a - c \<le> (b::ennreal)"
using ennreal_mono_minus[of 0 c a, THEN order_trans, of b] by simp
lemma ennreal_minus_le_iff: "a - b \<le> c \<longleftrightarrow> (a \<le> b + (c::ennreal) \<and> (a = top \<and> b = top \<longrightarrow> c = top))"
by (cases a; cases b; cases c)
(auto simp: top_unique top_add add_top ennreal_minus ennreal_plus[symmetric]
simp del: ennreal_plus)
lemma ennreal_le_minus_iff: "a \<le> b - c \<longleftrightarrow> (a + c \<le> (b::ennreal) \<or> (a = 0 \<and> b \<le> c))"
by (cases a; cases b; cases c)
(auto simp: top_unique top_add add_top ennreal_minus ennreal_plus[symmetric] ennreal_le_iff2
simp del: ennreal_plus)
lemma diff_add_eq_diff_diff_swap_ennreal: "x - (y + z :: ennreal) = x - y - z"
by (cases x; cases y; cases z)
(auto simp: ennreal_plus[symmetric] ennreal_minus_if add_top top_add simp del: ennreal_plus)
lemma diff_add_assoc2_ennreal: "b \<le> a \<Longrightarrow> (a - b + c::ennreal) = a + c - b"
by (cases a; cases b; cases c)
(auto simp add: ennreal_minus_if ennreal_plus_if add_top top_add top_unique simp del: ennreal_plus)
lemma diff_gt_0_iff_gt_ennreal: "0 < a - b \<longleftrightarrow> (a = top \<and> b = top \<or> b < (a::ennreal))"
by (cases a; cases b) (auto simp: ennreal_minus_if ennreal_less_iff)
lemma diff_eq_0_iff_ennreal: "(a - b::ennreal) = 0 \<longleftrightarrow> (a < top \<and> a \<le> b)"
by (cases a) (auto simp: ennreal_minus_eq_0 diff_eq_0_ennreal)
lemma add_diff_self_ennreal: "a + (b - a::ennreal) = (if a \<le> b then b else a)"
by (auto simp: diff_eq_0_iff_ennreal less_top)
lemma diff_add_self_ennreal: "(b - a + a::ennreal) = (if a \<le> b then b else a)"
by (auto simp: diff_add_cancel_ennreal diff_eq_0_iff_ennreal less_top)
lemma ennreal_minus_cancel_iff:
fixes a b c :: ennreal
shows "a - b = a - c \<longleftrightarrow> (b = c \<or> (a \<le> b \<and> a \<le> c) \<or> a = top)"
by (cases a; cases b; cases c) (auto simp: ennreal_minus_if)
lemma SUP_diff_ennreal:
"c < top \<Longrightarrow> (SUP i:I. f i - c :: ennreal) = (SUP i:I. f i) - c"
by (auto intro!: SUP_eqI ennreal_minus_mono SUP_least intro: SUP_upper
simp: ennreal_minus_cancel_iff ennreal_minus_le_iff less_top[symmetric])
lemma ennreal_SUP_add_right:
fixes c :: ennreal shows "I \<noteq> {} \<Longrightarrow> c + (SUP i:I. f i) = (SUP i:I. c + f i)"
using ennreal_SUP_add_left[of I f c] by (simp add: add.commute)
lemma SUP_add_directed_ennreal:
fixes f g :: "_ \<Rightarrow> ennreal"
assumes directed: "\<And>i j. i \<in> I \<Longrightarrow> j \<in> I \<Longrightarrow> \<exists>k\<in>I. f i + g j \<le> f k + g k"
shows "(SUP i:I. f i + g i) = (SUP i:I. f i) + (SUP i:I. g i)"
proof cases
assume "I = {}" then show ?thesis
by (simp add: bot_ereal_def)
next
assume "I \<noteq> {}"
show ?thesis
proof (rule antisym)
show "(SUP i:I. f i + g i) \<le> (SUP i:I. f i) + (SUP i:I. g i)"
by (rule SUP_least; intro add_mono SUP_upper)
next
have "(SUP i:I. f i) + (SUP i:I. g i) = (SUP i:I. f i + (SUP i:I. g i))"
by (intro ennreal_SUP_add_left[symmetric] \<open>I \<noteq> {}\<close>)
also have "\<dots> = (SUP i:I. (SUP j:I. f i + g j))"
by (intro SUP_cong refl ennreal_SUP_add_right \<open>I \<noteq> {}\<close>)
also have "\<dots> \<le> (SUP i:I. f i + g i)"
using directed by (intro SUP_least) (blast intro: SUP_upper2)
finally show "(SUP i:I. f i) + (SUP i:I. g i) \<le> (SUP i:I. f i + g i)" .
qed
qed
lemma enn2real_eq_0_iff: "enn2real x = 0 \<longleftrightarrow> x = 0 \<or> x = top"
by (cases x) auto
lemma (in -) continuous_on_diff_ereal:
"continuous_on A f \<Longrightarrow> continuous_on A g \<Longrightarrow> (\<And>x. x \<in> A \<Longrightarrow> \<bar>f x\<bar> \<noteq> \<infinity>) \<Longrightarrow> (\<And>x. x \<in> A \<Longrightarrow> \<bar>g x\<bar> \<noteq> \<infinity>) \<Longrightarrow> continuous_on A (\<lambda>z. f z - g z::ereal)"
apply (auto simp: continuous_on_def)
apply (intro tendsto_diff_ereal)
apply metis+
done
lemma (in -) continuous_on_diff_ennreal:
"continuous_on A f \<Longrightarrow> continuous_on A g \<Longrightarrow> (\<And>x. x \<in> A \<Longrightarrow> f x \<noteq> top) \<Longrightarrow> (\<And>x. x \<in> A \<Longrightarrow> g x \<noteq> top) \<Longrightarrow> continuous_on A (\<lambda>z. f z - g z::ennreal)"
including ennreal.lifting
proof (transfer fixing: A, simp add: top_ereal_def)
fix f g :: "'a \<Rightarrow> ereal" assume "\<forall>x. 0 \<le> f x" "\<forall>x. 0 \<le> g x" "continuous_on A f" "continuous_on A g"
moreover assume "f x \<noteq> \<infinity>" "g x \<noteq> \<infinity>" if "x \<in> A" for x
ultimately show "continuous_on A (\<lambda>z. max 0 (f z - g z))"
by (intro continuous_on_max continuous_on_const continuous_on_diff_ereal) auto
qed
lemma (in -) tendsto_diff_ennreal:
"(f \<longlongrightarrow> x) F \<Longrightarrow> (g \<longlongrightarrow> y) F \<Longrightarrow> x \<noteq> top \<Longrightarrow> y \<noteq> top \<Longrightarrow> ((\<lambda>z. f z - g z::ennreal) \<longlongrightarrow> x - y) F"
using continuous_on_tendsto_compose[where f="\<lambda>x. fst x - snd x::ennreal" and s="{(x, y). x \<noteq> top \<and> y \<noteq> top}" and g="\<lambda>x. (f x, g x)" and l="(x, y)" and F="F",
OF continuous_on_diff_ennreal]
by (auto simp: tendsto_Pair eventually_conj_iff less_top order_tendstoD continuous_on_fst continuous_on_snd continuous_on_id)
end