(* 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
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 of_nat_less[simp]:
"i < j \<Longrightarrow> of_nat i < (of_nat j::'a::{linordered_nonzero_semiring, semiring_char_0})"
by (auto simp: less_le)
lemma of_nat_le_iff[simp]:
"of_nat i \<le> (of_nat j::'a::{linordered_nonzero_semiring, semiring_char_0}) \<longleftrightarrow> i \<le> j"
proof (safe intro!: of_nat_mono)
assume "of_nat i \<le> (of_nat j::'a)" then show "i \<le> j"
proof (intro leI notI)
assume "j < i" from less_le_trans[OF of_nat_less[OF this] \<open>of_nat i \<le> of_nat j\<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 setsum_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> setsum f I \<le> suminf f"
by (rule sums_le[OF _ sums_If_finite_set summable_sums]) auto
typedef ennreal = "{x :: ereal. 0 \<le> x}"
morphisms enn2ereal e2ennreal'
by auto
definition "e2ennreal x = e2ennreal' (max 0 x)"
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'
lift_definition ennreal :: "real \<Rightarrow> ennreal" is "sup 0 \<circ> ereal"
by simp
declare [[coercion 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 "op \<le>" .
lift_definition less_ennreal :: "ennreal \<Rightarrow> ennreal \<Rightarrow> bool" is "op <" .
instance
by standard
(transfer ; auto simp: Inf_lower Inf_greatest Sup_upper Sup_least le_max_iff_disj max.absorb1)+
end
lemma ennreal_cases:
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
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 "op +" by simp
lift_definition times_ennreal :: "ennreal \<Rightarrow> ennreal \<Rightarrow> ennreal" is "op *" 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)"
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 (op \<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)
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)
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>
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" "x < y"
moreover from dense[OF this(2)] guess z ..
ultimately show "\<exists>z\<in>Collect (op \<le> 0). x < z \<and> z < y"
by (intro bexI[of _ z]) auto
qed
qed (rule open_ennreal_def)
end
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 "x < ereal (real_of_rat r)" "ereal (real_of_rat r) < y"
by auto
moreover 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
ultimately 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 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 enn2ereal_nonneg: "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 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
intro: le_less_trans less_imp_le)
lemma enn2ereal_Ioi: "enn2ereal -` {a <..} = (if 0 \<le> a then {e2ennreal a <..} else UNIV)"
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
intro: less_le_trans)
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 transfer_enn2ereal_continuous_on [transfer_rule]:
"rel_fun (op =) (rel_fun (rel_fun op = pcr_ennreal) op =) 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 enn2ereal_nonneg 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 continuous_on_add_ennreal[continuous_intros]:
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 (\<lambda>_. True) (op \<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 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_setsum_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_setsum_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 enn2ereal_eq_top_iff[simp]: "enn2ereal x = \<infinity> \<longleftrightarrow> x = top"
by transfer (simp add: top_ereal_def)
lemma ennreal_top_top: "top - top = (top::ennreal)"
by transfer (auto simp: top_ereal_def max_def)
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 enn2ereal_ennreal[simp]: "0 \<le> x \<Longrightarrow> enn2ereal (ennreal x) = x"
by transfer (simp add: max_absorb2)
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 ennreal_zero[simp]: "ennreal 0 = 0"
by (simp add: ennreal_def max.absorb1 zero_ennreal.abs_eq)
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 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 setsum_ennreal[simp]: "(\<And>i. i \<in> I \<Longrightarrow> 0 \<le> f i) \<Longrightarrow> (\<Sum>i\<in>I. ennreal (f i)) = ennreal (setsum f I)"
by (induction I rule: infinite_finite_induct) (auto simp: setsum_nonneg)
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 setsum_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 suminf_less_top: "(\<Sum>i. f i :: ennreal) < top \<Longrightarrow> f i < top"
using le_less_trans[OF setsum_le_suminf[OF summableI, of "{i}" f]] by simp
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 enn2ereal_top: "enn2ereal top = \<infinity>"
by transfer (simp add: top_ereal_def)
lemma e2ennreal_infty: "e2ennreal \<infinity> = top"
by (simp add: top_ennreal.abs_eq top_ereal_def)
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)
apply (auto simp: top_ereal_def[symmetric] sup_ereal_def[symmetric]
simp del: sup_ereal_def)
apply (auto simp add: top_ereal_def)
done
done
lemma bot_ennreal: "bot = (0::ennreal)"
by transfer rule
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_unfold[OF mf, symmetric])
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 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_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 ennreal_1[simp]: "ennreal 1 = 1"
by transfer (simp add: max_absorb2)
lemma ennreal_of_nat_eq_real_of_nat: "of_nat i = ennreal (of_nat i)"
by (induction i) simp_all
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 (auto simp: ennreal_of_nat_eq_real_of_nat ennreal_def less_ennreal.abs_eq eq_onp_def max.absorb2
dest!: one_less_of_natD intro: less_trans)
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 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 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 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
apply (cases a b c rule: ereal3_cases)
apply (auto simp: field_simps max_absorb2)
done
done
lemma ennreal_top_minus[simp]:
fixes c :: ennreal
shows "top - c = top"
by transfer (auto simp: top_ereal_def max_absorb2)
lemma le_ennreal_iff:
"0 \<le> r \<Longrightarrow> x \<le> ennreal r \<longleftrightarrow> (\<exists>q\<ge>0. x = ennreal q \<and> q \<le> r)"
apply (transfer fixing: r)
subgoal for x
by (cases x) (auto simp: max_absorb2 cong: conj_cong)
done
lemma ennreal_minus: "0 \<le> q \<Longrightarrow> q \<le> r \<Longrightarrow> ennreal r - ennreal q = ennreal (r - q)"
by transfer (simp add: max_absorb2)
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 *: "\<And>x. g x \<le> c \<Longrightarrow> 0 \<le> f x" "\<And>x. g x \<le> c \<Longrightarrow> g x = ennreal (f x)" "\<And>x. g x \<le> c \<Longrightarrow> f x \<le> r"
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 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 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_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: "0 \<le> a \<Longrightarrow> 0 \<le> b \<Longrightarrow> ennreal (a * b) = ennreal a * ennreal b"
by transfer (simp add: max_absorb2)
lemma setsum_enn2ereal[simp]: "(\<And>i. i \<in> I \<Longrightarrow> 0 \<le> f i) \<Longrightarrow> (\<Sum>i\<in>I. enn2ereal (f i)) = enn2ereal (setsum f I)"
by (induction I rule: infinite_finite_induct) (auto simp: setsum_nonneg zero_ennreal.rep_eq plus_ennreal.rep_eq)
lemma e2ennreal_enn2ereal[simp]: "e2ennreal (enn2ereal x) = x"
by (simp add: e2ennreal_def max_absorb2 enn2ereal_nonneg ennreal.enn2ereal_inverse)
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 sums_enn2ereal[simp]: "(\<lambda>i. enn2ereal (f i)) sums enn2ereal x \<longleftrightarrow> f sums x"
unfolding sums_def by (simp add: always_eventually setsum_nonneg setsum_enn2ereal)
lemma suminf_enn2real[simp]: "(\<Sum>i. enn2ereal (f i)) = enn2ereal (suminf f)"
by (rule sums_unique[symmetric]) (simp add: summable_sums)
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 op = pcr_ennreal f g \<longleftrightarrow> f = enn2ereal \<circ> g"
by (auto simp: rel_fun_def ennreal.pcr_cr_eq cr_ennreal_def)
lemma transfer_e2ennreal_suminf [transfer_rule]: "rel_fun (rel_fun op = 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_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 ennreal_eq_zero_iff[simp]: "0 \<le> x \<Longrightarrow> ennreal x = 0 \<longleftrightarrow> x = 0"
by transfer (auto simp: max_absorb2)
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 ennreal_of_nat_neq_top[simp]: "of_nat i \<noteq> (top::ennreal)"
by (induction i) auto
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)
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
lemma ennreal_suminf_lessD: "(\<Sum>i. f i :: ennreal) < x \<Longrightarrow> f i < x"
using le_less_trans[OF setsum_le_suminf[OF summableI, of "{i}" f]] by simp
lemma ennreal_less_top[simp]: "ennreal x < top"
by transfer (simp add: top_ereal_def max_def)
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_less_zero_iff[simp]: "0 < ennreal x \<longleftrightarrow> 0 < x"
by transfer (auto simp: max_def)
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 transfer_e2ennreal_sumset [transfer_rule]:
"rel_fun (rel_fun op = pcr_ennreal) (rel_fun op = pcr_ennreal) setsum setsum"
by (auto intro!: rel_funI simp: rel_fun_eq_pcr_ennreal comp_def)
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 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 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 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 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_power: "0 \<le> r \<Longrightarrow> ennreal r ^ n = ennreal (r ^ n)"
by (induction n) (auto simp: ennreal_mult)
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 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 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 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
lemma ennreal_half[simp]: "ennreal (1/2) = inverse 2"
by transfer (simp add: max.absorb2)
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 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 ennreal_add_bot[simp]: "bot + x = (x::ennreal)"
by transfer simp
lemma sup_continuous_transfer[transfer_rule]:
"(rel_fun (rel_fun (op =) pcr_ennreal) op =) 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 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)
lemmas ennreal2_cases = ennreal_cases[case_product ennreal_cases]
lemmas ennreal3_cases = ennreal_cases[case_product ennreal2_cases]
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_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_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 ennreal_less: "0 \<le> r \<Longrightarrow> ennreal r < ennreal q \<longleftrightarrow> r < q"
unfolding not_le[symmetric] by auto
lemma ennreal_numeral_less_top[simp]: "numeral i < (top::ennreal)"
using of_nat_less_top[of "numeral i"] by simp
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
definition "enn2real x = real_of_ereal (enn2ereal x)"
lemma enn2real_nonneg: "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 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 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_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 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_SUP_setsum:
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_setsum incseq_def SUP_upper2 max_absorb2 setsum_nonneg)
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 rel_fun_liminf[transfer_rule]: "rel_fun (rel_fun op = pcr_ennreal) pcr_ennreal liminf liminf"
proof -
have "rel_fun (rel_fun op = 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 enn2ereal_nonneg rel_fun_eq_pcr_ennreal)
done
qed
lemma rel_fun_limsup[transfer_rule]: "rel_fun (rel_fun op = pcr_ennreal) pcr_ennreal limsup limsup"
proof -
have "rel_fun (rel_fun op = 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 enn2ereal_nonneg rel_fun_eq_pcr_ennreal)
apply (subst (asm) max.absorb2)
apply (rule SUP_upper2)
apply (auto simp: enn2ereal_nonneg)
done
qed
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 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_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)
end