diff -r 965769fe2b63 -r fc1556774cfe src/HOL/Probability/Measure_Space.thy --- a/src/HOL/Probability/Measure_Space.thy Mon Dec 07 16:48:10 2015 +0000 +++ b/src/HOL/Probability/Measure_Space.thy Mon Dec 07 20:19:59 2015 +0100 @@ -4,7 +4,7 @@ Author: Armin Heller, TU München *) -section {* Measure spaces and their properties *} +section \Measure spaces and their properties\ theory Measure_Space imports @@ -19,7 +19,7 @@ shows "(\n. f n * indicator (A n) x) = f i" proof - have **: "\n. f n * indicator (A n) x = (if n = i then f n else 0 :: ereal)" - using `x \ A i` assms unfolding disjoint_family_on_def indicator_def by auto + using \x \ A i\ assms unfolding disjoint_family_on_def indicator_def by auto then have "\n. (\j (\i. A i)" then obtain i where "x \ A i" by auto - from suminf_cmult_indicator[OF assms(1), OF `x \ A i`, of "\k. 1"] + from suminf_cmult_indicator[OF assms(1), OF \x \ A i\, of "\k. 1"] show ?thesis using * by simp qed simp @@ -47,17 +47,17 @@ shows "(\i\P. f i * indicator (A i) x) = f j" proof - have "P \ {i. x \ A i} = {j}" - using d `x \ A j` `j \ P` unfolding disjoint_family_on_def + using d \x \ A j\ \j \ P\ unfolding disjoint_family_on_def by auto thus ?thesis unfolding indicator_def - by (simp add: if_distrib setsum.If_cases[OF `finite P`]) + by (simp add: if_distrib setsum.If_cases[OF \finite P\]) qed -text {* +text \ The type for emeasure spaces is already defined in @{theory Sigma_Algebra}, as it is also used to represent sigma algebras (with an arbitrary emeasure). -*} +\ subsection "Extend binary sets" @@ -91,12 +91,12 @@ shows "f {} = 0 \ (\n. f (binaryset A B n)) = f A + f B" by (metis binaryset_sums sums_unique) -subsection {* Properties of a premeasure @{term \} *} +subsection \Properties of a premeasure @{term \}\ -text {* +text \ The definitions for @{const positive} and @{const countably_additive} should be here, by they are necessary to define @{typ "'a measure"} in @{theory Sigma_Algebra}. -*} +\ definition additive where "additive M \ \ (\x\M. \y\M. x \ y = {} \ \ (x \ y) = \ x + \ y)" @@ -134,7 +134,7 @@ also have "\ = f (A n \ disjointed A (Suc n))" using A by (subst f(2)[THEN additiveD]) (auto simp: disjointed_mono) also have "A n \ disjointed A (Suc n) = A (Suc n)" - using `incseq A` by (auto dest: incseq_SucD simp: disjointed_mono) + using \incseq A\ by (auto dest: incseq_SucD simp: disjointed_mono) finally show ?case . qed simp @@ -144,7 +144,7 @@ and A: "A`S \ M" and disj: "disjoint_family_on A S" shows "(\i\S. f (A i)) = f (\i\S. A i)" - using `finite S` disj A + using \finite S\ disj A proof induct case empty show ?case using f by (simp add: positive_def) next @@ -154,7 +154,7 @@ moreover have "A s \ M" using insert by blast moreover have "(\i\S. A i) \ M" - using insert `finite S` by auto + using insert \finite S\ by auto ultimately have "f (A s \ (\i\S. A i)) = f (A s) + f(\i\S. A i)" using ad UNION_in_sets A by (auto simp add: additive_def) with insert show ?case using ad disjoint_family_on_mono[of S "insert s S" A] @@ -254,7 +254,7 @@ by (metis F(2) assms(1) infinite_super sets_into_space) have F_subset: "{i. \ (F i) \ 0} \ {i. F i \ {}}" - by (auto simp: positiveD_empty[OF `positive M \`]) + by (auto simp: positiveD_empty[OF \positive M \\]) moreover have fin_not_empty: "finite {i. F i \ {}}" proof (rule finite_imageD) from f have "f`{i. F i \ {}} \ (\i. F i)" by auto @@ -272,7 +272,7 @@ also have "\ = (\i | F i \ {}. \ (F i))" using fin_not_empty F_subset by (rule setsum.mono_neutral_left) auto also have "\ = \ (\i\{i. F i \ {}}. F i)" - using `positive M \` `additive M \` fin_not_empty disj_not_empty F by (intro additive_sum) auto + using \positive M \\ \additive M \\ fin_not_empty disj_not_empty F by (intro additive_sum) auto also have "\ = \ (\i. F i)" by (rule arg_cong[where f=\]) auto finally show "(\i. \ (F i)) = \ (\i. F i)" . @@ -327,7 +327,7 @@ assume cont: "(\A. range A \ M \ decseq A \ (\i. A i) \ M \ (\i. f (A i) \ \) \ (\i. f (A i)) ----> f (\i. A i))" fix A :: "nat \ 'a set" assume A: "range A \ M" "decseq A" "(\i. A i) = {}" "\i. f (A i) \ \" with cont[THEN spec, of A] show "(\i. f (A i)) ----> 0" - using `positive M f`[unfolded positive_def] by auto + using \positive M f\[unfolded positive_def] by auto next assume cont: "\A. range A \ M \ decseq A \ (\i. A i) = {} \ (\i. f (A i) \ \) \ (\i. f (A i)) ----> 0" fix A :: "nat \ 'a set" assume A: "range A \ M" "decseq A" "(\i. A i) \ M" "\i. f (A i) \ \" @@ -415,7 +415,7 @@ using empty_continuous_imp_continuous_from_below[OF f fin] cont by blast -subsection {* Properties of @{const emeasure} *} +subsection \Properties of @{const emeasure}\ lemma emeasure_positive: "positive (sets M) (emeasure M)" by (cases M) (auto simp: sets_def emeasure_def Abs_measure_inverse measure_space_def) @@ -483,7 +483,7 @@ by (rule plus_emeasure[symmetric]) (auto simp add: s) finally have "emeasure M (space M) = emeasure M s + emeasure M (space M - s)" . then show ?thesis - using fin `0 \ emeasure M s` + using fin \0 \ emeasure M s\ unfolding ereal_eq_minus_iff by (auto simp: ac_simps) qed @@ -493,13 +493,13 @@ shows "emeasure M (A - B) = emeasure M A - emeasure M B" proof - have "0 \ emeasure M B" using assms by auto - have "(A - B) \ B = A" using `B \ A` by auto + have "(A - B) \ B = A" using \B \ A\ by auto then have "emeasure M A = emeasure M ((A - B) \ B)" by simp also have "\ = emeasure M (A - B) + emeasure M B" by (subst plus_emeasure[symmetric]) auto finally show "emeasure M (A - B) = emeasure M A - emeasure M B" unfolding ereal_eq_minus_iff - using finite `0 \ emeasure M B` by auto + using finite \0 \ emeasure M B\ by auto qed lemma Lim_emeasure_incseq: @@ -541,13 +541,13 @@ unfolding minus_ereal_def using A0 assms by (subst SUP_ereal_add) (auto simp add: decseq_emeasure) also have "\ = (SUP n. emeasure M (A 0 - A n))" - using A finite `decseq A`[unfolded decseq_def] by (subst emeasure_Diff) auto + using A finite \decseq A\[unfolded decseq_def] by (subst emeasure_Diff) auto also have "\ = emeasure M (\i. A 0 - A i)" proof (rule SUP_emeasure_incseq) show "range (\n. A 0 - A n) \ sets M" using A by auto show "incseq (\n. A 0 - A n)" - using `decseq A` by (auto simp add: incseq_def decseq_def) + using \decseq A\ by (auto simp add: incseq_def decseq_def) qed also have "\ = emeasure M (A 0) - emeasure M (\i. A i)" using A finite * by (simp, subst emeasure_Diff) auto @@ -616,7 +616,7 @@ proof - have "emeasure M {x\space M. lfp F x} = emeasure M (\i. {x\space M. (F ^^ i) (\x. False) x})" using sup_continuous_lfp[OF cont] by (auto simp add: bot_fun_def intro!: arg_cong2[where f=emeasure]) - moreover { fix i from `P M` have "{x\space M. (F ^^ i) (\x. False) x} \ sets M" + moreover { fix i from \P M\ have "{x\space M. (F ^^ i) (\x. False) x} \ sets M" by (induct i arbitrary: M) (auto simp add: pred_def[symmetric] intro: *) } moreover have "incseq (\i. {x\space M. (F ^^ i) (\x. False) x})" proof (rule incseq_SucI) @@ -694,7 +694,7 @@ assumes sets: "{x} \ sets M" "A \ sets M" and "x \ A" shows "emeasure M (insert x A) = emeasure M {x} + emeasure M A" proof - - have "{x} \ A = {}" using `x \ A` by auto + have "{x} \ A = {}" using \x \ A\ by auto from plus_emeasure[OF sets this] show ?thesis by simp qed @@ -717,7 +717,7 @@ have "(\i\S. emeasure M (A \ (B i))) = emeasure M (\i\S. A \ (B i))" proof (rule setsum_emeasure) show "disjoint_family_on (\i. A \ B i) S" - using `disjoint_family_on B S` + using \disjoint_family_on B S\ unfolding disjoint_family_on_def by auto qed (insert assms, auto) also have "(\i\S. A \ (B i)) = A" @@ -747,11 +747,11 @@ fix X assume "X \ sets M" then have X: "X \ A" by auto then have "emeasure M X = (\a\X. emeasure M {a})" - using `finite A` by (subst emeasure_eq_setsum_singleton) (auto dest: finite_subset) + using \finite A\ by (subst emeasure_eq_setsum_singleton) (auto dest: finite_subset) also have "\ = (\a\X. emeasure N {a})" using X eq by (auto intro!: setsum.cong) also have "\ = emeasure N X" - using X `finite A` by (subst emeasure_eq_setsum_singleton) (auto dest: finite_subset) + using X \finite A\ by (subst emeasure_eq_setsum_singleton) (auto dest: finite_subset) finally show "emeasure M X = emeasure N X" . qed simp @@ -767,18 +767,18 @@ let ?\ = "emeasure M" and ?\ = "emeasure N" interpret S: sigma_algebra \ "sigma_sets \ E" by (rule sigma_algebra_sigma_sets) fact have "space M = \" - using sets.top[of M] sets.space_closed[of M] S.top S.space_closed `sets M = sigma_sets \ E` + using sets.top[of M] sets.space_closed[of M] S.top S.space_closed \sets M = sigma_sets \ E\ by blast { fix F D assume "F \ E" and "?\ F \ \" then have [intro]: "F \ sigma_sets \ E" by auto - have "?\ F \ \" using `?\ F \ \` `F \ E` eq by simp + have "?\ F \ \" using \?\ F \ \\ \F \ E\ eq by simp assume "D \ sets M" - with `Int_stable E` `E \ Pow \` have "emeasure M (F \ D) = emeasure N (F \ D)" + with \Int_stable E\ \E \ Pow \\ have "emeasure M (F \ D) = emeasure N (F \ D)" unfolding M proof (induct rule: sigma_sets_induct_disjoint) case (basic A) - then have "F \ A \ E" using `Int_stable E` `F \ E` by (auto simp: Int_stable_def) + then have "F \ A \ E" using \Int_stable E\ \F \ E\ by (auto simp: Int_stable_def) then show ?case using eq by auto next case empty then show ?case by simp @@ -786,19 +786,19 @@ case (compl A) then have **: "F \ (\ - A) = F - (F \ A)" and [intro]: "F \ A \ sigma_sets \ E" - using `F \ E` S.sets_into_space by (auto simp: M) + using \F \ E\ S.sets_into_space by (auto simp: M) have "?\ (F \ A) \ ?\ F" by (auto intro!: emeasure_mono simp: M N) - then have "?\ (F \ A) \ \" using `?\ F \ \` by auto + then have "?\ (F \ A) \ \" using \?\ F \ \\ by auto have "?\ (F \ A) \ ?\ F" by (auto intro!: emeasure_mono simp: M N) - then have "?\ (F \ A) \ \" using `?\ F \ \` by auto + then have "?\ (F \ A) \ \" using \?\ F \ \\ by auto then have "?\ (F \ (\ - A)) = ?\ F - ?\ (F \ A)" unfolding ** - using `F \ A \ sigma_sets \ E` by (auto intro!: emeasure_Diff simp: M N) - also have "\ = ?\ F - ?\ (F \ A)" using eq `F \ E` compl by simp + using \F \ A \ sigma_sets \ E\ by (auto intro!: emeasure_Diff simp: M N) + also have "\ = ?\ F - ?\ (F \ A)" using eq \F \ E\ compl by simp also have "\ = ?\ (F \ (\ - A))" unfolding ** - using `F \ A \ sigma_sets \ E` `?\ (F \ A) \ \` + using \F \ A \ sigma_sets \ E\ \?\ (F \ A) \ \\ by (auto intro!: emeasure_Diff[symmetric] simp: M N) finally show ?case - using `space M = \` by auto + using \space M = \\ by auto next case (union A) then have "?\ (\x. F \ A x) = ?\ (\x. F \ A x)" @@ -815,10 +815,10 @@ using A(1) by (auto simp: subset_eq M) fix F assume "F \ sets M" let ?D = "disjointed (\i. F \ A i)" - from `space M = \` have F_eq: "F = (\i. ?D i)" - using `F \ sets M`[THEN sets.sets_into_space] A(2)[symmetric] by (auto simp: UN_disjointed_eq) + from \space M = \\ have F_eq: "F = (\i. ?D i)" + using \F \ sets M\[THEN sets.sets_into_space] A(2)[symmetric] by (auto simp: UN_disjointed_eq) have [simp, intro]: "\i. ?D i \ sets M" - using sets.range_disjointed_sets[of "\i. F \ A i" M] `F \ sets M` + using sets.range_disjointed_sets[of "\i. F \ A i" M] \F \ sets M\ by (auto simp: subset_eq) have "disjoint_family ?D" by (auto simp: disjoint_family_disjointed) @@ -832,7 +832,7 @@ using *[of "A i" "?D i", OF _ A(3)] A(1) by auto qed ultimately show "emeasure M F = emeasure N F" - by (simp add: image_subset_iff `sets M = sets N`[symmetric] F_eq[symmetric] suminf_emeasure) + by (simp add: image_subset_iff \sets M = sets N\[symmetric] F_eq[symmetric] suminf_emeasure) qed qed @@ -845,7 +845,7 @@ by (simp add: emeasure_countably_additive) qed simp_all -subsection {* @{text \}-null sets *} +subsection \\\\-null sets\ definition null_sets :: "'a measure \ 'a set set" where "null_sets M = {N\sets M. emeasure M N = 0}" @@ -901,10 +901,10 @@ show "(\i\I. N i) \ sets M" using assms by (intro sets.countable_UN') auto have "emeasure M (\i\I. N i) \ (\n. emeasure M (N (from_nat_into I n)))" - unfolding UN_from_nat_into[OF `countable I` `I \ {}`] - using assms `I \ {}` by (intro emeasure_subadditive_countably) (auto intro: from_nat_into) + unfolding UN_from_nat_into[OF \countable I\ \I \ {}\] + using assms \I \ {}\ by (intro emeasure_subadditive_countably) (auto intro: from_nat_into) also have "(\n. emeasure M (N (from_nat_into I n))) = (\_. 0)" - using assms `I \ {}` by (auto intro: from_nat_into) + using assms \I \ {}\ by (auto intro: from_nat_into) finally show "emeasure M (\i\I. N i) = 0" by (intro antisym emeasure_nonneg) simp qed @@ -953,7 +953,7 @@ by (subst plus_emeasure[symmetric]) auto qed -subsection {* The almost everywhere filter (i.e.\ quantifier) *} +subsection \The almost everywhere filter (i.e.\ quantifier)\ definition ae_filter :: "'a measure \ 'a filter" where "ae_filter M = (INF N:null_sets M. principal (space M - N))" @@ -983,7 +983,7 @@ have "0 \ emeasure M ?P" by auto moreover have "emeasure M ?P \ emeasure M N" using assms N(1,2) by (auto intro: emeasure_mono) - ultimately have "emeasure M ?P = 0" unfolding `emeasure M N = 0` by auto + ultimately have "emeasure M ?P = 0" unfolding \emeasure M N = 0\ by auto then show "?P \ null_sets M" using assms by auto next assume "?P \ null_sets M" with assms show "AE x in M. P x" by (auto intro: AE_I') @@ -1138,7 +1138,7 @@ lemma AE_finite_allI: assumes "finite S" shows "(\s. s \ S \ AE x in M. Q s x) \ AE x in M. \s\S. Q s x" - using AE_finite_all[OF `finite S`] by auto + using AE_finite_all[OF \finite S\] by auto lemma emeasure_mono_AE: assumes imp: "AE x in M. x \ A \ x \ B" @@ -1187,7 +1187,7 @@ finally show ?thesis . qed -subsection {* @{text \}-finite Measures *} +subsection \\\\-finite Measures\ locale sigma_finite_measure = fixes M :: "'a measure" @@ -1204,19 +1204,19 @@ using sigma_finite_countable by metis show thesis proof cases - assume "A = {}" with `(\A) = space M` show thesis + assume "A = {}" with \(\A) = space M\ show thesis by (intro that[of "\_. {}"]) auto next assume "A \ {}" show thesis proof show "range (from_nat_into A) \ sets M" - using `A \ {}` A by auto + using \A \ {}\ A by auto have "(\i. from_nat_into A i) = \A" - using range_from_nat_into[OF `A \ {}` `countable A`] by auto + using range_from_nat_into[OF \A \ {}\ \countable A\] by auto with A show "(\i. from_nat_into A i) = space M" by auto - qed (intro A from_nat_into `A \ {}`) + qed (intro A from_nat_into \A \ {}\) qed qed @@ -1275,7 +1275,7 @@ qed qed -subsection {* Measure space induced by distribution of @{const measurable}-functions *} +subsection \Measure space induced by distribution of @{const measurable}-functions\ definition distr :: "'a measure \ 'b measure \ ('a \ 'b) \ 'b measure" where "distr M N f = measure_of (space N) (sets N) (\A. emeasure M (f -` A \ space M))" @@ -1312,7 +1312,7 @@ moreover have "(\i. f -` A i \ space M) \ sets M" using * by blast moreover have **: "disjoint_family (\i. f -` A i \ space M)" - using `disjoint_family A` by (auto simp: disjoint_family_on_def) + using \disjoint_family A\ by (auto simp: disjoint_family_on_def) ultimately show "(\i. ?\ (A i)) = ?\ (\i. A i)" using suminf_emeasure[OF _ **] A f by (auto simp: comp_def vimage_UN) @@ -1334,21 +1334,21 @@ shows "emeasure M' {x\space M'. lfp F (f x)} = (SUP i. emeasure M' {x\space M'. (F ^^ i) (\x. False) (f x)})" proof (subst (1 2) emeasure_Collect_distr[symmetric, where X=f]) show "f \ measurable M' M" "f \ measurable M' M" - using f[OF `P M`] by auto + using f[OF \P M\] by auto { fix i show "Measurable.pred M ((F ^^ i) (\x. False))" - using `P M` by (induction i arbitrary: M) (auto intro!: *) } + using \P M\ by (induction i arbitrary: M) (auto intro!: *) } show "Measurable.pred M (lfp F)" - using `P M` cont * by (rule measurable_lfp_coinduct[of P]) + using \P M\ cont * by (rule measurable_lfp_coinduct[of P]) have "emeasure (distr M' M f) {x \ space (distr M' M f). lfp F x} = (SUP i. emeasure (distr M' M f) {x \ space (distr M' M f). (F ^^ i) (\x. False) x})" - using `P M` + using \P M\ proof (coinduction arbitrary: M rule: emeasure_lfp') case (measurable A N) then have "\N. P N \ Measurable.pred (distr M' N f) A" by metis then have "\N. P N \ Measurable.pred N A" by simp - with `P N`[THEN *] show ?case + with \P N\[THEN *] show ?case by auto qed fact then show "emeasure (distr M' M f) {x \ space M. lfp F x} = @@ -1405,7 +1405,7 @@ by (auto simp add: emeasure_distr measurable_space intro!: arg_cong[where f="emeasure M"] measure_eqI) -subsection {* Real measure values *} +subsection \Real measure values\ lemma measure_nonneg: "0 \ measure M A" using emeasure_nonneg[of M A] unfolding measure_def by (auto intro: real_of_ereal_pos) @@ -1449,7 +1449,7 @@ using measurable by (auto intro!: emeasure_mono) hence "measure M ((A - B) \ B) = measure M (A - B) + measure M B" using measurable finite by (rule_tac measure_Union) auto - thus ?thesis using `B \ A` by (auto simp: Un_absorb2) + thus ?thesis using \B \ A\ by (auto simp: Un_absorb2) qed lemma measure_UNION: @@ -1548,7 +1548,7 @@ by (intro lim_real_of_ereal) simp qed -subsection {* Measure spaces with @{term "emeasure M (space M) < \"} *} +subsection \Measure spaces with @{term "emeasure M (space M) < \"}\ locale finite_measure = sigma_finite_measure M for M + assumes finite_emeasure_space: "emeasure M (space M) \ \" @@ -1606,7 +1606,7 @@ assumes A: "range A \ sets M" and sum: "summable (\i. measure M (A i))" shows "measure M (\i. A i) \ (\i. measure M (A i))" proof - - from `summable (\i. measure M (A i))` + from \summable (\i. measure M (A i))\ have "(\i. ereal (measure M (A i))) sums ereal (\i. measure M (A i))" by (simp add: sums_ereal) (rule summable_sums) from sums_unique[OF this, symmetric] @@ -1729,7 +1729,7 @@ shows "measure M e = (\ x \ s. measure M (e \ f x))" proof - have e: "e = (\i \ s. e \ f i)" - using `e \ sets M` sets.sets_into_space upper by blast + using \e \ sets M\ sets.sets_into_space upper by blast hence "measure M e = measure M (\i \ s. e \ f i)" by simp also have "\ = (\ x \ s. measure M (e \ f x))" proof (rule finite_measure_finite_Union) @@ -1774,7 +1774,7 @@ using bound[of x] sets_eq_imp_space_eq[OF sets] by (simp add: iter) qed (auto simp add: iter le_fun_def INF_apply[abs_def] intro!: meas cont) -subsection {* Counting space *} +subsection \Counting space\ lemma strict_monoI_Suc: assumes ord [simp]: "(\n. f n < f (Suc n))" shows "strict_mono f" @@ -1789,7 +1789,7 @@ (is "_ = ?M X") unfolding count_space_def proof (rule emeasure_measure_of_sigma) - show "X \ Pow A" using `X \ A` by auto + show "X \ Pow A" using \X \ A\ by auto show "sigma_algebra A (Pow A)" by (rule sigma_algebra_Pow) show positive: "positive (Pow A) ?M" by (auto simp: positive_def) @@ -1806,7 +1806,7 @@ proof cases assume "\i. \j\i. F i = F j" then guess i .. note i = this - { fix j from i `incseq F` have "F j \ F i" + { fix j from i \incseq F\ have "F j \ F i" by (cases "i \ j") (auto simp: incseq_def) } then have eq: "(\i. F i) = F i" by auto @@ -1815,11 +1815,11 @@ next assume "\ (\i. \j\i. F i = F j)" then obtain f where f: "\i. i \ f i" "\i. F i \ F (f i)" by metis - then have "\i. F i \ F (f i)" using `incseq F` by (auto simp: incseq_def) + then have "\i. F i \ F (f i)" using \incseq F\ by (auto simp: incseq_def) with f have *: "\i. F i \ F (f i)" by auto have "incseq (\i. ?M (F i))" - using `incseq F` unfolding incseq_def by (auto simp: card_mono dest: finite_subset) + using \incseq F\ unfolding incseq_def by (auto simp: card_mono dest: finite_subset) then have "(\i. ?M (F i)) ----> (SUP n. ?M (F n))" by (rule LIMSEQ_SUP) @@ -1830,9 +1830,9 @@ case (Suc n) then guess k .. note k = this moreover have "finite (F k) \ finite (F (f k)) \ card (F k) < card (F (f k))" - using `F k \ F (f k)` by (simp add: psubset_card_mono) + using \F k \ F (f k)\ by (simp add: psubset_card_mono) moreover have "finite (F (f k)) \ finite (F k)" - using `k \ f k` `incseq F` by (auto simp: incseq_def dest: finite_subset) + using \k \ f k\ \incseq F\ by (auto simp: incseq_def dest: finite_subset) ultimately show ?case by (auto intro!: exI[of _ "f k"]) qed auto @@ -1926,7 +1926,7 @@ show "sigma_finite_measure (count_space A)" .. qed -subsection {* Measure restricted to space *} +subsection \Measure restricted to space\ lemma emeasure_restrict_space: assumes "\ \ space M \ sets M" "A \ \" @@ -1936,7 +1936,7 @@ show ?thesis proof (rule emeasure_measure_of[OF restrict_space_def]) show "op \ \ ` sets M \ Pow (\ \ space M)" "A \ sets (restrict_space M \)" - using `A \ \` `A \ sets M` sets.space_closed by (auto simp: sets_restrict_space) + using \A \ \\ \A \ sets M\ sets.space_closed by (auto simp: sets_restrict_space) show "positive (sets (restrict_space M \)) (emeasure M)" by (auto simp: positive_def emeasure_nonneg) show "countably_additive (sets (restrict_space M \)) (emeasure M)" @@ -2085,7 +2085,7 @@ finally show "emeasure M X = emeasure N X" . qed fact -subsection {* Null measure *} +subsection \Null measure\ definition "null_measure M = sigma (space M) (sets M)"