src/HOL/BNF_Cardinal_Arithmetic.thy
changeset 76951 293caf3dbecd
parent 75625 0dd3ac5fdbaa
child 76952 f552cf789a8d
--- a/src/HOL/BNF_Cardinal_Arithmetic.thy	Fri Jan 13 22:47:40 2023 +0000
+++ b/src/HOL/BNF_Cardinal_Arithmetic.thy	Sat Jan 14 16:53:54 2023 +0000
@@ -8,35 +8,37 @@
 section \<open>Cardinal Arithmetic as Needed by Bounded Natural Functors\<close>
 
 theory BNF_Cardinal_Arithmetic
-imports BNF_Cardinal_Order_Relation
+  imports BNF_Cardinal_Order_Relation
 begin
 
 lemma dir_image: "\<lbrakk>\<And>x y. (f x = f y) = (x = y); Card_order r\<rbrakk> \<Longrightarrow> r =o dir_image r f"
-by (rule dir_image_ordIso) (auto simp add: inj_on_def card_order_on_def)
+  by (rule dir_image_ordIso) (auto simp add: inj_on_def card_order_on_def)
 
 lemma card_order_dir_image:
   assumes bij: "bij f" and co: "card_order r"
   shows "card_order (dir_image r f)"
 proof -
-  from assms have "Field (dir_image r f) = UNIV"
-    using card_order_on_Card_order[of UNIV r] unfolding bij_def dir_image_Field by auto
-  moreover from bij have "\<And>x y. (f x = f y) = (x = y)" unfolding bij_def inj_on_def by auto
+  have "Field (dir_image r f) = UNIV"
+    using assms card_order_on_Card_order[of UNIV r] 
+    unfolding bij_def dir_image_Field by auto
+  moreover from bij have "\<And>x y. (f x = f y) = (x = y)" 
+    unfolding bij_def inj_on_def by auto
   with co have "Card_order (dir_image r f)"
-    using card_order_on_Card_order[of UNIV r] Card_order_ordIso2[OF _ dir_image] by blast
+    using card_order_on_Card_order Card_order_ordIso2[OF _ dir_image] by blast
   ultimately show ?thesis by auto
 qed
 
 lemma ordIso_refl: "Card_order r \<Longrightarrow> r =o r"
-by (rule card_order_on_ordIso)
+  by (rule card_order_on_ordIso)
 
 lemma ordLeq_refl: "Card_order r \<Longrightarrow> r \<le>o r"
-by (rule ordIso_imp_ordLeq, rule card_order_on_ordIso)
+  by (rule ordIso_imp_ordLeq, rule card_order_on_ordIso)
 
 lemma card_of_ordIso_subst: "A = B \<Longrightarrow> |A| =o |B|"
-by (simp only: ordIso_refl card_of_Card_order)
+  by (simp only: ordIso_refl card_of_Card_order)
 
 lemma Field_card_order: "card_order r \<Longrightarrow> Field r = UNIV"
-using card_order_on_Card_order[of UNIV r] by simp
+  using card_order_on_Card_order[of UNIV r] by simp
 
 
 subsection \<open>Zero\<close>
@@ -44,13 +46,12 @@
 definition czero where
   "czero = card_of {}"
 
-lemma czero_ordIso:
-  "czero =o czero"
-using card_of_empty_ordIso by (simp add: czero_def)
+lemma czero_ordIso: "czero =o czero"
+  using card_of_empty_ordIso by (simp add: czero_def)
 
 lemma card_of_ordIso_czero_iff_empty:
   "|A| =o (czero :: 'b rel) \<longleftrightarrow> A = ({} :: 'a set)"
-unfolding czero_def by (rule iffI[OF card_of_empty2]) (auto simp: card_of_refl card_of_empty_ordIso)
+  unfolding czero_def by (rule iffI[OF card_of_empty2]) (auto simp: card_of_refl card_of_empty_ordIso)
 
 (* A "not czero" Cardinal predicate *)
 abbreviation Cnotzero where
@@ -62,28 +63,21 @@
 
 lemma czeroI:
   "\<lbrakk>Card_order r; Field r = {}\<rbrakk> \<Longrightarrow> r =o czero"
-using Cnotzero_imp_not_empty ordIso_transitive[OF _ czero_ordIso] by blast
+  using Cnotzero_imp_not_empty ordIso_transitive[OF _ czero_ordIso] by blast
 
 lemma czeroE:
   "r =o czero \<Longrightarrow> Field r = {}"
-unfolding czero_def
-by (drule card_of_cong) (simp only: Field_card_of card_of_empty2)
+  unfolding czero_def
+  by (drule card_of_cong) (simp only: Field_card_of card_of_empty2)
 
 lemma Cnotzero_mono:
   "\<lbrakk>Cnotzero r; Card_order q; r \<le>o q\<rbrakk> \<Longrightarrow> Cnotzero q"
-apply (rule ccontr)
-apply auto
-apply (drule czeroE)
-apply (erule notE)
-apply (erule czeroI)
-apply (drule card_of_mono2)
-apply (simp only: card_of_empty3)
-done
+    by (force intro: czeroI dest: card_of_mono2 card_of_empty3 czeroE)
 
 subsection \<open>(In)finite cardinals\<close>
 
 definition cinfinite where
-  "cinfinite r = (\<not> finite (Field r))"
+  "cinfinite r \<equiv> (\<not> finite (Field r))"
 
 abbreviation Cinfinite where
   "Cinfinite r \<equiv> cinfinite r \<and> Card_order r"
@@ -101,7 +95,7 @@
 lemmas natLeq_card_order = natLeq_Card_order[unfolded Field_natLeq]
 
 lemma natLeq_cinfinite: "cinfinite natLeq"
-unfolding cinfinite_def Field_natLeq by (rule infinite_UNIV_nat)
+  unfolding cinfinite_def Field_natLeq by (rule infinite_UNIV_nat)
 
 lemma natLeq_Cinfinite: "Cinfinite natLeq"
   using natLeq_cinfinite natLeq_Card_order by simp
@@ -117,50 +111,46 @@
 qed
 
 lemma cinfinite_not_czero: "cinfinite r \<Longrightarrow> \<not> (r =o (czero :: 'a rel))"
-unfolding cinfinite_def by (cases "Field r = {}") (auto dest: czeroE)
+  unfolding cinfinite_def by (cases "Field r = {}") (auto dest: czeroE)
 
 lemma Cinfinite_Cnotzero: "Cinfinite r \<Longrightarrow> Cnotzero r"
-by (rule conjI[OF cinfinite_not_czero]) simp_all
+  using cinfinite_not_czero by auto
 
 lemma Cinfinite_cong: "\<lbrakk>r1 =o r2; Cinfinite r1\<rbrakk> \<Longrightarrow> Cinfinite r2"
-using Card_order_ordIso2[of r1 r2] unfolding cinfinite_def ordIso_iff_ordLeq
-by (auto dest: card_of_ordLeq_infinite[OF card_of_mono2])
+  using Card_order_ordIso2[of r1 r2] unfolding cinfinite_def ordIso_iff_ordLeq
+  by (auto dest: card_of_ordLeq_infinite[OF card_of_mono2])
 
 lemma cinfinite_mono: "\<lbrakk>r1 \<le>o r2; cinfinite r1\<rbrakk> \<Longrightarrow> cinfinite r2"
-unfolding cinfinite_def by (auto dest: card_of_ordLeq_infinite[OF card_of_mono2])
+  unfolding cinfinite_def by (auto dest: card_of_ordLeq_infinite[OF card_of_mono2])
 
 lemma regularCard_ordIso:
-assumes  "k =o k'" and "Cinfinite k" and "regularCard k"
-shows "regularCard k'"
+  assumes  "k =o k'" and "Cinfinite k" and "regularCard k"
+  shows "regularCard k'"
 proof-
   have "stable k" using assms cinfinite_def regularCard_stable by blast
   hence "stable k'" using assms stable_ordIso1 ordIso_symmetric by blast
-  thus ?thesis using assms cinfinite_def stable_regularCard
-    using Cinfinite_cong by blast
+  thus ?thesis using assms cinfinite_def stable_regularCard Cinfinite_cong by blast
 qed
 
 corollary card_of_UNION_ordLess_infinite_Field_regularCard:
-assumes ST: "regularCard r" and INF: "Cinfinite r" and
-        LEQ_I: "|I| <o r" and LEQ: "\<forall>i \<in> I. |A i| <o r"
-      shows "|\<Union>i \<in> I. A i| <o r"
+  assumes "regularCard r" and "Cinfinite r" and "|I| <o r" and "\<forall>i \<in> I. |A i| <o r"
+  shows "|\<Union>i \<in> I. A i| <o r"
   using card_of_UNION_ordLess_infinite_Field regularCard_stable assms cinfinite_def by blast
 
 subsection \<open>Binary sum\<close>
 
-definition csum (infixr "+c" 65) where
-  "r1 +c r2 \<equiv> |Field r1 <+> Field r2|"
+definition csum (infixr "+c" 65) 
+    where "r1 +c r2 \<equiv> |Field r1 <+> Field r2|"
 
 lemma Field_csum: "Field (r +c s) = Inl ` Field r \<union> Inr ` Field s"
   unfolding csum_def Field_card_of by auto
 
-lemma Card_order_csum:
-  "Card_order (r1 +c r2)"
-unfolding csum_def by (simp add: card_of_Card_order)
+lemma Card_order_csum: "Card_order (r1 +c r2)"
+  unfolding csum_def by (simp add: card_of_Card_order)
 
-lemma csum_Cnotzero1:
-  "Cnotzero r1 \<Longrightarrow> Cnotzero (r1 +c r2)"
-unfolding csum_def using Cnotzero_imp_not_empty[of r1] Plus_eq_empty_conv[of "Field r1" "Field r2"]
-   card_of_ordIso_czero_iff_empty[of "Field r1 <+> Field r2"] by (auto intro: card_of_Card_order)
+lemma csum_Cnotzero1: "Cnotzero r1 \<Longrightarrow> Cnotzero (r1 +c r2)"
+  using Cnotzero_imp_not_empty 
+  by (auto intro: card_of_Card_order simp: csum_def card_of_ordIso_czero_iff_empty)
 
 lemma card_order_csum:
   assumes "card_order r1" "card_order r2"
@@ -172,49 +162,45 @@
 
 lemma cinfinite_csum:
   "cinfinite r1 \<or> cinfinite r2 \<Longrightarrow> cinfinite (r1 +c r2)"
-unfolding cinfinite_def csum_def by (auto simp: Field_card_of)
-
-lemma Cinfinite_csum1:
-  "Cinfinite r1 \<Longrightarrow> Cinfinite (r1 +c r2)"
-unfolding cinfinite_def csum_def by (rule conjI[OF _ card_of_Card_order]) (auto simp: Field_card_of)
+  unfolding cinfinite_def csum_def by (auto simp: Field_card_of)
 
 lemma Cinfinite_csum:
   "Cinfinite r1 \<or> Cinfinite r2 \<Longrightarrow> Cinfinite (r1 +c r2)"
-unfolding cinfinite_def csum_def by (rule conjI[OF _ card_of_Card_order]) (auto simp: Field_card_of)
+  using card_of_Card_order 
+  by (auto simp: cinfinite_def csum_def Field_card_of)
 
-lemma Cinfinite_csum_weak:
-  "\<lbrakk>Cinfinite r1; Cinfinite r2\<rbrakk> \<Longrightarrow> Cinfinite (r1 +c r2)"
-by (erule Cinfinite_csum1)
+lemma Cinfinite_csum1: "Cinfinite r1 \<Longrightarrow> Cinfinite (r1 +c r2)"
+  by (blast intro!: Cinfinite_csum elim: )
 
 lemma csum_cong: "\<lbrakk>p1 =o r1; p2 =o r2\<rbrakk> \<Longrightarrow> p1 +c p2 =o r1 +c r2"
-by (simp only: csum_def ordIso_Plus_cong)
+  by (simp only: csum_def ordIso_Plus_cong)
 
 lemma csum_cong1: "p1 =o r1 \<Longrightarrow> p1 +c q =o r1 +c q"
-by (simp only: csum_def ordIso_Plus_cong1)
+  by (simp only: csum_def ordIso_Plus_cong1)
 
 lemma csum_cong2: "p2 =o r2 \<Longrightarrow> q +c p2 =o q +c r2"
-by (simp only: csum_def ordIso_Plus_cong2)
+  by (simp only: csum_def ordIso_Plus_cong2)
 
 lemma csum_mono: "\<lbrakk>p1 \<le>o r1; p2 \<le>o r2\<rbrakk> \<Longrightarrow> p1 +c p2 \<le>o r1 +c r2"
-by (simp only: csum_def ordLeq_Plus_mono)
+  by (simp only: csum_def ordLeq_Plus_mono)
 
 lemma csum_mono1: "p1 \<le>o r1 \<Longrightarrow> p1 +c q \<le>o r1 +c q"
-by (simp only: csum_def ordLeq_Plus_mono1)
+  by (simp only: csum_def ordLeq_Plus_mono1)
 
 lemma csum_mono2: "p2 \<le>o r2 \<Longrightarrow> q +c p2 \<le>o q +c r2"
-by (simp only: csum_def ordLeq_Plus_mono2)
+  by (simp only: csum_def ordLeq_Plus_mono2)
 
 lemma ordLeq_csum1: "Card_order p1 \<Longrightarrow> p1 \<le>o p1 +c p2"
-by (simp only: csum_def Card_order_Plus1)
+  by (simp only: csum_def Card_order_Plus1)
 
 lemma ordLeq_csum2: "Card_order p2 \<Longrightarrow> p2 \<le>o p1 +c p2"
-by (simp only: csum_def Card_order_Plus2)
+  by (simp only: csum_def Card_order_Plus2)
 
 lemma csum_com: "p1 +c p2 =o p2 +c p1"
-by (simp only: csum_def card_of_Plus_commute)
+  by (simp only: csum_def card_of_Plus_commute)
 
 lemma csum_assoc: "(p1 +c p2) +c p3 =o p1 +c p2 +c p3"
-by (simp only: csum_def Field_card_of card_of_Plus_assoc)
+  by (simp only: csum_def Field_card_of card_of_Plus_assoc)
 
 lemma Cfinite_csum: "\<lbrakk>Cfinite r; Cfinite s\<rbrakk> \<Longrightarrow> Cfinite (r +c s)"
   unfolding cfinite_def csum_def Field_card_of using card_of_card_order_on by simp
@@ -235,10 +221,10 @@
 qed
 
 lemma Plus_csum: "|A <+> B| =o |A| +c |B|"
-by (simp only: csum_def Field_card_of card_of_refl)
+  by (simp only: csum_def Field_card_of card_of_refl)
 
 lemma Un_csum: "|A \<union> B| \<le>o |A| +c |B|"
-using ordLeq_ordIso_trans[OF card_of_Un_Plus_ordLeq Plus_csum] by blast
+  using ordLeq_ordIso_trans[OF card_of_Un_Plus_ordLeq Plus_csum] by blast
 
 subsection \<open>One\<close>
 
@@ -246,16 +232,17 @@
   "cone = card_of {()}"
 
 lemma Card_order_cone: "Card_order cone"
-unfolding cone_def by (rule card_of_Card_order)
+  unfolding cone_def by (rule card_of_Card_order)
 
 lemma Cfinite_cone: "Cfinite cone"
   unfolding cfinite_def by (simp add: Card_order_cone)
 
 lemma cone_not_czero: "\<not> (cone =o czero)"
-unfolding czero_def cone_def ordIso_iff_ordLeq using card_of_empty3 empty_not_insert by blast
+  unfolding czero_def cone_def ordIso_iff_ordLeq 
+  using card_of_empty3 empty_not_insert by blast
 
 lemma cone_ordLeq_Cnotzero: "Cnotzero r \<Longrightarrow> cone \<le>o r"
-unfolding cone_def by (rule Card_order_singl_ordLeq) (auto intro: czeroI)
+  unfolding cone_def by (rule Card_order_singl_ordLeq) (auto intro: czeroI)
 
 
 subsection \<open>Two\<close>
@@ -264,14 +251,14 @@
   "ctwo = |UNIV :: bool set|"
 
 lemma Card_order_ctwo: "Card_order ctwo"
-unfolding ctwo_def by (rule card_of_Card_order)
+  unfolding ctwo_def by (rule card_of_Card_order)
 
 lemma ctwo_not_czero: "\<not> (ctwo =o czero)"
-using card_of_empty3[of "UNIV :: bool set"] ordIso_iff_ordLeq
-unfolding czero_def ctwo_def using UNIV_not_empty by auto
+  using card_of_empty3[of "UNIV :: bool set"] ordIso_iff_ordLeq
+  unfolding czero_def ctwo_def using UNIV_not_empty by auto
 
 lemma ctwo_Cnotzero: "Cnotzero ctwo"
-by (simp add: ctwo_not_czero Card_order_ctwo)
+  by (simp add: ctwo_not_czero Card_order_ctwo)
 
 
 subsection \<open>Family sum\<close>
@@ -288,7 +275,7 @@
   "CSUM i:r. rs" == "CONST Csum r (%i. rs)"
 
 lemma SIGMA_CSUM: "|SIGMA i : I. As i| = (CSUM i : |I|. |As i| )"
-by (auto simp: Csum_def Field_card_of)
+  by (auto simp: Csum_def Field_card_of)
 
 (* NB: Always, under the cardinal operator,
 operations on sets are reduced automatically to operations on cardinals.
@@ -304,49 +291,50 @@
   assumes "card_order r1" "card_order r2"
   shows "card_order (r1 *c r2)"
 proof -
-  have "Field r1 = UNIV" "Field r2 = UNIV" using assms card_order_on_Card_order by auto
+  have "Field r1 = UNIV" "Field r2 = UNIV" 
+    using assms card_order_on_Card_order by auto
   thus ?thesis by (auto simp: cprod_def card_of_card_order_on)
 qed
 
 lemma Card_order_cprod: "Card_order (r1 *c r2)"
-by (simp only: cprod_def Field_card_of card_of_card_order_on)
+  by (simp only: cprod_def Field_card_of card_of_card_order_on)
 
 lemma cprod_mono1: "p1 \<le>o r1 \<Longrightarrow> p1 *c q \<le>o r1 *c q"
-by (simp only: cprod_def ordLeq_Times_mono1)
+  by (simp only: cprod_def ordLeq_Times_mono1)
 
 lemma cprod_mono2: "p2 \<le>o r2 \<Longrightarrow> q *c p2 \<le>o q *c r2"
-by (simp only: cprod_def ordLeq_Times_mono2)
+  by (simp only: cprod_def ordLeq_Times_mono2)
 
 lemma cprod_mono: "\<lbrakk>p1 \<le>o r1; p2 \<le>o r2\<rbrakk> \<Longrightarrow> p1 *c p2 \<le>o r1 *c r2"
-by (rule ordLeq_transitive[OF cprod_mono1 cprod_mono2])
+  by (rule ordLeq_transitive[OF cprod_mono1 cprod_mono2])
 
 lemma ordLeq_cprod2: "\<lbrakk>Cnotzero p1; Card_order p2\<rbrakk> \<Longrightarrow> p2 \<le>o p1 *c p2"
-unfolding cprod_def by (rule Card_order_Times2) (auto intro: czeroI)
+  unfolding cprod_def by (rule Card_order_Times2) (auto intro: czeroI)
 
 lemma cinfinite_cprod: "\<lbrakk>cinfinite r1; cinfinite r2\<rbrakk> \<Longrightarrow> cinfinite (r1 *c r2)"
-by (simp add: cinfinite_def cprod_def Field_card_of infinite_cartesian_product)
+  by (simp add: cinfinite_def cprod_def Field_card_of infinite_cartesian_product)
 
 lemma cinfinite_cprod2: "\<lbrakk>Cnotzero r1; Cinfinite r2\<rbrakk> \<Longrightarrow> cinfinite (r1 *c r2)"
-by (rule cinfinite_mono) (auto intro: ordLeq_cprod2)
+  by (rule cinfinite_mono) (auto intro: ordLeq_cprod2)
 
 lemma Cinfinite_cprod2: "\<lbrakk>Cnotzero r1; Cinfinite r2\<rbrakk> \<Longrightarrow> Cinfinite (r1 *c r2)"
-by (blast intro: cinfinite_cprod2 Card_order_cprod)
+  by (blast intro: cinfinite_cprod2 Card_order_cprod)
 
 lemma cprod_cong: "\<lbrakk>p1 =o r1; p2 =o r2\<rbrakk> \<Longrightarrow> p1 *c p2 =o r1 *c r2"
-unfolding ordIso_iff_ordLeq by (blast intro: cprod_mono)
+  unfolding ordIso_iff_ordLeq by (blast intro: cprod_mono)
 
 lemma cprod_cong1: "\<lbrakk>p1 =o r1\<rbrakk> \<Longrightarrow> p1 *c p2 =o r1 *c p2"
-unfolding ordIso_iff_ordLeq by (blast intro: cprod_mono1)
+  unfolding ordIso_iff_ordLeq by (blast intro: cprod_mono1)
 
 lemma cprod_cong2: "p2 =o r2 \<Longrightarrow> q *c p2 =o q *c r2"
-unfolding ordIso_iff_ordLeq by (blast intro: cprod_mono2)
+  unfolding ordIso_iff_ordLeq by (blast intro: cprod_mono2)
 
 lemma cprod_com: "p1 *c p2 =o p2 *c p1"
-by (simp only: cprod_def card_of_Times_commute)
+  by (simp only: cprod_def card_of_Times_commute)
 
 lemma card_of_Csum_Times:
   "\<forall>i \<in> I. |A i| \<le>o |B| \<Longrightarrow> (CSUM i : |I|. |A i| ) \<le>o |I| *c |B|"
-by (simp only: Csum_def cprod_def Field_card_of card_of_Sigma_mono1)
+  by (simp only: Csum_def cprod_def Field_card_of card_of_Sigma_mono1)
 
 lemma card_of_Csum_Times':
   assumes "Card_order r" "\<forall>i \<in> I. |A i| \<le>o r"
@@ -361,27 +349,33 @@
 qed
 
 lemma cprod_csum_distrib1: "r1 *c r2 +c r1 *c r3 =o r1 *c (r2 +c r3)"
-unfolding csum_def cprod_def by (simp add: Field_card_of card_of_Times_Plus_distrib ordIso_symmetric)
+  unfolding csum_def cprod_def by (simp add: Field_card_of card_of_Times_Plus_distrib ordIso_symmetric)
 
 lemma csum_absorb2': "\<lbrakk>Card_order r2; r1 \<le>o r2; cinfinite r1 \<or> cinfinite r2\<rbrakk> \<Longrightarrow> r1 +c r2 =o r2"
-unfolding csum_def by (rule conjunct2[OF Card_order_Plus_infinite])
-  (auto simp: cinfinite_def dest: cinfinite_mono)
+  unfolding csum_def 
+  using Card_order_Plus_infinite
+  by (fastforce simp: cinfinite_def dest: cinfinite_mono)
 
 lemma csum_absorb1':
   assumes card: "Card_order r2"
-  and r12: "r1 \<le>o r2" and cr12: "cinfinite r1 \<or> cinfinite r2"
+    and r12: "r1 \<le>o r2" and cr12: "cinfinite r1 \<or> cinfinite r2"
   shows "r2 +c r1 =o r2"
-by (rule ordIso_transitive, rule csum_com, rule csum_absorb2', (simp only: assms)+)
+proof -
+  have "r1 +c r2 =o r2"
+    by (simp add: csum_absorb2' assms)
+  then show ?thesis
+    by (blast intro: ordIso_transitive csum_com)
+qed
 
 lemma csum_absorb1: "\<lbrakk>Cinfinite r2; r1 \<le>o r2\<rbrakk> \<Longrightarrow> r2 +c r1 =o r2"
-by (rule csum_absorb1') auto
+  by (rule csum_absorb1') auto
 
 lemma csum_absorb2: "\<lbrakk>Cinfinite r2 ; r1 \<le>o r2\<rbrakk> \<Longrightarrow> r1 +c r2 =o r2"
   using ordIso_transitive csum_com csum_absorb1 by blast
 
 lemma regularCard_csum:
   assumes "Cinfinite r" "Cinfinite s" "regularCard r" "regularCard s"
-    shows "regularCard (r +c s)"
+  shows "regularCard (r +c s)"
 proof (cases "r \<le>o s")
   case True
   then show ?thesis using regularCard_ordIso[of s] csum_absorb2'[THEN ordIso_symmetric] assms by auto
@@ -394,9 +388,9 @@
 
 lemma csum_mono_strict:
   assumes Card_order: "Card_order r" "Card_order q"
-  and Cinfinite: "Cinfinite r'" "Cinfinite q'"
-  and less: "r <o r'" "q <o q'"
-shows "r +c q <o r' +c q'"
+    and Cinfinite: "Cinfinite r'" "Cinfinite q'"
+    and less: "r <o r'" "q <o q'"
+  shows "r +c q <o r' +c q'"
 proof -
   have Well_order: "Well_order r" "Well_order q" "Well_order r'" "Well_order q'"
     using card_order_on_well_order_on Card_order Cinfinite by auto
@@ -434,7 +428,7 @@
     proof (cases "Cinfinite q")
       case True
       then have "r \<le>o q" using finite_ordLess_infinite cinfinite_def cfinite_def outer Well_order
-        ordLess_imp_ordLeq by blast
+          ordLess_imp_ordLeq by blast
       then have "r +c q =o q" by (rule csum_absorb2[OF True])
       then show ?thesis using ordIso_ordLess_trans ordLess_ordLeq_trans less ordLeq_csum2 Cinfinite by blast
     next
@@ -453,11 +447,11 @@
   "r1 ^c r2 \<equiv> |Func (Field r2) (Field r1)|"
 
 lemma Card_order_cexp: "Card_order (r1 ^c r2)"
-unfolding cexp_def by (rule card_of_Card_order)
+  unfolding cexp_def by (rule card_of_Card_order)
 
 lemma cexp_mono':
   assumes 1: "p1 \<le>o r1" and 2: "p2 \<le>o r2"
-  and n: "Field p2 = {} \<Longrightarrow> Field r2 = {}"
+    and n: "Field p2 = {} \<Longrightarrow> Field r2 = {}"
   shows "p1 ^c p2 \<le>o r1 ^c r2"
 proof(cases "Field p1 = {}")
   case True
@@ -498,36 +492,36 @@
 
 lemma cexp_mono:
   assumes 1: "p1 \<le>o r1" and 2: "p2 \<le>o r2"
-  and n: "p2 =o czero \<Longrightarrow> r2 =o czero" and card: "Card_order p2"
+    and n: "p2 =o czero \<Longrightarrow> r2 =o czero" and card: "Card_order p2"
   shows "p1 ^c p2 \<le>o r1 ^c r2"
   by (rule cexp_mono'[OF 1 2 czeroE[OF n[OF czeroI[OF card]]]])
 
 lemma cexp_mono1:
   assumes 1: "p1 \<le>o r1" and q: "Card_order q"
   shows "p1 ^c q \<le>o r1 ^c q"
-using ordLeq_refl[OF q] by (rule cexp_mono[OF 1]) (auto simp: q)
+  using ordLeq_refl[OF q] by (rule cexp_mono[OF 1]) (auto simp: q)
 
 lemma cexp_mono2':
   assumes 2: "p2 \<le>o r2" and q: "Card_order q"
-  and n: "Field p2 = {} \<Longrightarrow> Field r2 = {}"
+    and n: "Field p2 = {} \<Longrightarrow> Field r2 = {}"
   shows "q ^c p2 \<le>o q ^c r2"
-using ordLeq_refl[OF q] by (rule cexp_mono'[OF _ 2 n]) auto
+  using ordLeq_refl[OF q] by (rule cexp_mono'[OF _ 2 n]) auto
 
 lemma cexp_mono2:
   assumes 2: "p2 \<le>o r2" and q: "Card_order q"
-  and n: "p2 =o czero \<Longrightarrow> r2 =o czero" and card: "Card_order p2"
+    and n: "p2 =o czero \<Longrightarrow> r2 =o czero" and card: "Card_order p2"
   shows "q ^c p2 \<le>o q ^c r2"
-using ordLeq_refl[OF q] by (rule cexp_mono[OF _ 2 n card]) auto
+  using ordLeq_refl[OF q] by (rule cexp_mono[OF _ 2 n card]) auto
 
 lemma cexp_mono2_Cnotzero:
   assumes "p2 \<le>o r2" "Card_order q" "Cnotzero p2"
   shows "q ^c p2 \<le>o q ^c r2"
-using assms(3) czeroI by (blast intro: cexp_mono2'[OF assms(1,2)])
+  using assms(3) czeroI by (blast intro: cexp_mono2'[OF assms(1,2)])
 
 lemma cexp_cong:
   assumes 1: "p1 =o r1" and 2: "p2 =o r2"
-  and Cr: "Card_order r2"
-  and Cp: "Card_order p2"
+    and Cr: "Card_order r2"
+    and Cp: "Card_order p2"
   shows "p1 ^c p2 =o r1 ^c r2"
 proof -
   obtain f where "bij_betw f (Field p2) (Field r2)"
@@ -535,7 +529,7 @@
   hence 0: "Field p2 = {} \<longleftrightarrow> Field r2 = {}" unfolding bij_betw_def by auto
   have r: "p2 =o czero \<Longrightarrow> r2 =o czero"
     and p: "r2 =o czero \<Longrightarrow> p2 =o czero"
-     using 0 Cr Cp czeroE czeroI by auto
+    using 0 Cr Cp czeroE czeroI by auto
   show ?thesis using 0 1 2 unfolding ordIso_iff_ordLeq
     using r p cexp_mono[OF _ _ _ Cp] cexp_mono[OF _ _ _ Cr] by blast
 qed
@@ -543,12 +537,12 @@
 lemma cexp_cong1:
   assumes 1: "p1 =o r1" and q: "Card_order q"
   shows "p1 ^c q =o r1 ^c q"
-by (rule cexp_cong[OF 1 _ q q]) (rule ordIso_refl[OF q])
+  by (rule cexp_cong[OF 1 _ q q]) (rule ordIso_refl[OF q])
 
 lemma cexp_cong2:
   assumes 2: "p2 =o r2" and q: "Card_order q" and p: "Card_order p2"
   shows "q ^c p2 =o q ^c r2"
-by (rule cexp_cong[OF _ 2]) (auto simp only: ordIso_refl Card_order_ordIso2[OF p 2] q p)
+  by (rule cexp_cong[OF _ 2]) (auto simp only: ordIso_refl Card_order_ordIso2[OF p 2] q p)
 
 lemma cexp_cone:
   assumes "Card_order r"
@@ -570,31 +564,30 @@
     unfolding cprod_def cexp_def Field_card_of
     using card_of_Func_Times by(rule ordIso_symmetric)
   also have "r1 ^c (r3 *c r2) =o ?R"
-    apply(rule cexp_cong2) using cprod_com r1 by (auto simp: Card_order_cprod)
+    using cprod_com r1 by (intro cexp_cong2, auto simp: Card_order_cprod)
   finally show ?thesis .
 qed
 
 lemma cprod_infinite1': "\<lbrakk>Cinfinite r; Cnotzero p; p \<le>o r\<rbrakk> \<Longrightarrow> r *c p =o r"
-unfolding cinfinite_def cprod_def
-by (rule Card_order_Times_infinite[THEN conjunct1]) (blast intro: czeroI)+
+  unfolding cinfinite_def cprod_def
+  by (rule Card_order_Times_infinite[THEN conjunct1]) (blast intro: czeroI)+
 
 lemma cprod_infinite: "Cinfinite r \<Longrightarrow> r *c r =o r"
-using cprod_infinite1' Cinfinite_Cnotzero ordLeq_refl by blast
+  using cprod_infinite1' Cinfinite_Cnotzero ordLeq_refl by blast
 
 lemma cexp_cprod_ordLeq:
   assumes r1: "Card_order r1" and r2: "Cinfinite r2"
-  and r3: "Cnotzero r3" "r3 \<le>o r2"
+    and r3: "Cnotzero r3" "r3 \<le>o r2"
   shows "(r1 ^c r2) ^c r3 =o r1 ^c r2" (is "?L =o ?R")
 proof-
   have "?L =o r1 ^c (r2 *c r3)" using cexp_cprod[OF r1] .
   also have "r1 ^c (r2 *c r3) =o ?R"
-  apply(rule cexp_cong2)
-  apply(rule cprod_infinite1'[OF r2 r3]) using r1 r2 by (fastforce simp: Card_order_cprod)+
+    using assms by (fastforce simp: Card_order_cprod intro: cprod_infinite1' cexp_cong2)
   finally show ?thesis .
 qed
 
 lemma Cnotzero_UNIV: "Cnotzero |UNIV|"
-by (auto simp: card_of_Card_order card_of_ordIso_czero_iff_empty)
+  by (auto simp: card_of_Card_order card_of_ordIso_czero_iff_empty)
 
 lemma ordLess_ctwo_cexp:
   assumes "Card_order r"
@@ -613,21 +606,12 @@
   case True thus ?thesis by (simp only: card_of_empty cexp_def czero_def ordIso_ordLeq_trans)
 next
   case False
-  thus ?thesis
-    apply -
-    apply (rule ordIso_ordLeq_trans)
-    apply (rule ordIso_symmetric)
-    apply (rule cexp_cone)
-    apply (rule assms(2))
-    apply (rule cexp_mono2)
-    apply (rule cone_ordLeq_Cnotzero)
-    apply (rule assms(1))
-    apply (rule assms(2))
-    apply (rule notE)
-    apply (rule cone_not_czero)
-    apply assumption
-    apply (rule Card_order_cone)
-  done
+  have "q =o q ^c cone"
+    by (blast intro: assms ordIso_symmetric cexp_cone)
+  also have "q ^c cone \<le>o q ^c r"
+    using assms
+    by (intro cexp_mono2) (simp_all add: cone_ordLeq_Cnotzero cone_not_czero Card_order_cone)
+  finally show ?thesis .
 qed
 
 lemma ordLeq_cexp2:
@@ -636,24 +620,20 @@
 proof (cases "r =o (czero :: 'a rel)")
   case True thus ?thesis by (simp only: card_of_empty cexp_def czero_def ordIso_ordLeq_trans)
 next
-  case False thus ?thesis
-    apply -
-    apply (rule ordLess_imp_ordLeq)
-    apply (rule ordLess_ordLeq_trans)
-    apply (rule ordLess_ctwo_cexp)
-    apply (rule assms(2))
-    apply (rule cexp_mono1)
-    apply (rule assms(1))
-    apply (rule assms(2))
-  done
+  case False 
+  have "r <o ctwo ^c r"
+    by (blast intro: assms ordLess_ctwo_cexp) 
+  also have "ctwo ^c r \<le>o q ^c r"
+    by (blast intro: assms cexp_mono1)
+  finally show ?thesis by (rule ordLess_imp_ordLeq)
 qed
 
 lemma cinfinite_cexp: "\<lbrakk>ctwo \<le>o q; Cinfinite r\<rbrakk> \<Longrightarrow> cinfinite (q ^c r)"
-by (rule cinfinite_mono[OF ordLeq_cexp2]) simp_all
+  by (rule cinfinite_mono[OF ordLeq_cexp2]) simp_all
 
 lemma Cinfinite_cexp:
   "\<lbrakk>ctwo \<le>o q; Cinfinite r\<rbrakk> \<Longrightarrow> Cinfinite (q ^c r)"
-by (simp add: cinfinite_cexp Card_order_cexp)
+  by (simp add: cinfinite_cexp Card_order_cexp)
 
 lemma card_order_cexp:
   assumes "card_order r1" "card_order r2"
@@ -664,32 +644,32 @@
 qed
 
 lemma ctwo_ordLess_natLeq: "ctwo <o natLeq"
-unfolding ctwo_def using finite_UNIV natLeq_cinfinite natLeq_Card_order
-by (intro Cfinite_ordLess_Cinfinite) (auto simp: cfinite_def card_of_Card_order)
+  unfolding ctwo_def using finite_UNIV natLeq_cinfinite natLeq_Card_order
+  by (intro Cfinite_ordLess_Cinfinite) (auto simp: cfinite_def card_of_Card_order)
 
 lemma ctwo_ordLess_Cinfinite: "Cinfinite r \<Longrightarrow> ctwo <o r"
-by (rule ordLess_ordLeq_trans[OF ctwo_ordLess_natLeq natLeq_ordLeq_cinfinite])
+  by (rule ordLess_ordLeq_trans[OF ctwo_ordLess_natLeq natLeq_ordLeq_cinfinite])
 
 lemma ctwo_ordLeq_Cinfinite:
   assumes "Cinfinite r"
   shows "ctwo \<le>o r"
-by (rule ordLess_imp_ordLeq[OF ctwo_ordLess_Cinfinite[OF assms]])
+  by (rule ordLess_imp_ordLeq[OF ctwo_ordLess_Cinfinite[OF assms]])
 
 lemma Un_Cinfinite_bound: "\<lbrakk>|A| \<le>o r; |B| \<le>o r; Cinfinite r\<rbrakk> \<Longrightarrow> |A \<union> B| \<le>o r"
-by (auto simp add: cinfinite_def card_of_Un_ordLeq_infinite_Field)
+  by (auto simp add: cinfinite_def card_of_Un_ordLeq_infinite_Field)
 
 lemma Un_Cinfinite_bound_strict: "\<lbrakk>|A| <o r; |B| <o r; Cinfinite r\<rbrakk> \<Longrightarrow> |A \<union> B| <o r"
-by (auto simp add: cinfinite_def card_of_Un_ordLess_infinite_Field)
+  by (auto simp add: cinfinite_def card_of_Un_ordLess_infinite_Field)
 
 lemma UNION_Cinfinite_bound: "\<lbrakk>|I| \<le>o r; \<forall>i \<in> I. |A i| \<le>o r; Cinfinite r\<rbrakk> \<Longrightarrow> |\<Union>i \<in> I. A i| \<le>o r"
-by (auto simp add: card_of_UNION_ordLeq_infinite_Field cinfinite_def)
+  by (auto simp add: card_of_UNION_ordLeq_infinite_Field cinfinite_def)
 
 lemma csum_cinfinite_bound:
   assumes "p \<le>o r" "q \<le>o r" "Card_order p" "Card_order q" "Cinfinite r"
   shows "p +c q \<le>o r"
 proof -
-  from assms(1-4) have "|Field p| \<le>o r" "|Field q| \<le>o r"
-    unfolding card_order_on_def using card_of_least ordLeq_transitive by blast+
+  have "|Field p| \<le>o r" "|Field q| \<le>o r"
+    using assms card_of_least ordLeq_transitive unfolding card_order_on_def by blast+
   with assms show ?thesis unfolding cinfinite_def csum_def
     by (blast intro: card_of_Plus_ordLeq_infinite_Field)
 qed
@@ -711,26 +691,22 @@
 
 lemma regularCard_cprod:
   assumes "Cinfinite r" "Cinfinite s" "regularCard r" "regularCard s"
-    shows "regularCard (r *c s)"
+  shows "regularCard (r *c s)"
 proof (cases "r \<le>o s")
   case True
-  show ?thesis
-    apply (rule regularCard_ordIso[of s])
-      apply (rule ordIso_symmetric[OF cprod_infinite2'])
-    using assms True Cinfinite_Cnotzero by auto
+  with assms Cinfinite_Cnotzero show ?thesis
+    by (force intro: regularCard_ordIso ordIso_symmetric[OF cprod_infinite2'])
 next
   case False
   have "Well_order r" "Well_order s" using assms card_order_on_well_order_on by auto
-  then have 1: "s \<le>o r" using not_ordLeq_iff_ordLess ordLess_imp_ordLeq False by blast
-  show ?thesis
-    apply (rule regularCard_ordIso[of r])
-      apply (rule ordIso_symmetric[OF cprod_infinite1'])
-    using assms 1 Cinfinite_Cnotzero by auto
+  then have "s \<le>o r" using not_ordLeq_iff_ordLess ordLess_imp_ordLeq False by blast
+  with assms Cinfinite_Cnotzero show ?thesis
+    by (force intro: regularCard_ordIso ordIso_symmetric[OF cprod_infinite1'])
 qed
 
 lemma cprod_csum_cexp:
   "r1 *c r2 \<le>o (r1 +c r2) ^c ctwo"
-unfolding cprod_def csum_def cexp_def ctwo_def Field_card_of
+  unfolding cprod_def csum_def cexp_def ctwo_def Field_card_of
 proof -
   let ?f = "\<lambda>(a, b). %x. if x then Inl a else Inr b"
   have "inj_on ?f (Field r1 \<times> Field r2)" (is "inj_on _ ?LHS")
@@ -742,8 +718,8 @@
 qed
 
 lemma Cfinite_cprod_Cinfinite: "\<lbrakk>Cfinite r; Cinfinite s\<rbrakk> \<Longrightarrow> r *c s \<le>o s"
-by (intro cprod_cinfinite_bound)
-  (auto intro: ordLeq_refl ordLess_imp_ordLeq[OF Cfinite_ordLess_Cinfinite])
+  by (intro cprod_cinfinite_bound)
+    (auto intro: ordLeq_refl ordLess_imp_ordLeq[OF Cfinite_ordLess_Cinfinite])
 
 lemma cprod_cexp: "(r *c s) ^c t =o r ^c t *c s ^c t"
   unfolding cprod_def cexp_def Field_card_of by (rule Func_Times_Range)
@@ -807,12 +783,12 @@
 (* cardSuc *)
 
 lemma Cinfinite_cardSuc: "Cinfinite r \<Longrightarrow> Cinfinite (cardSuc r)"
-by (simp add: cinfinite_def cardSuc_Card_order cardSuc_finite)
+  by (simp add: cinfinite_def cardSuc_Card_order cardSuc_finite)
 
 lemma cardSuc_UNION_Cinfinite:
   assumes "Cinfinite r" "relChain (cardSuc r) As" "B \<le> (\<Union>i \<in> Field (cardSuc r). As i)" "|B| <=o r"
   shows "\<exists>i \<in> Field (cardSuc r). B \<le> As i"
-using cardSuc_UNION assms unfolding cinfinite_def by blast
+  using cardSuc_UNION assms unfolding cinfinite_def by blast
 
 lemma Cinfinite_card_suc: "\<lbrakk> Cinfinite r ; card_order r \<rbrakk> \<Longrightarrow> Cinfinite (card_suc r)"
   using Cinfinite_cong[OF cardSuc_ordIso_card_suc Cinfinite_cardSuc] .