src/HOL/Lattices.thy

 locale semilattice = abel_semigroup +
   assumes idem [simp]: "a \<^bold>* a = a"
 begin
 
 lemma left_idem [simp]: "a \<^bold>* (a \<^bold>* b) = a \<^bold>* b"
-by (simp add: assoc [symmetric])
+  by (simp add: assoc [symmetric])
 
 lemma right_idem [simp]: "(a \<^bold>* b) \<^bold>* b = a \<^bold>* b"
-by (simp add: assoc)
+  by (simp add: assoc)
 
 end
 
 locale semilattice_neutr = semilattice + comm_monoid
 
 locale semilattice_order = semilattice +
-  fixes less_eq :: "'a \<Rightarrow> 'a \<Rightarrow> bool" (infix "\<^bold>\<le>" 50)
-    and less :: "'a \<Rightarrow> 'a \<Rightarrow> bool" (infix "\<^bold><" 50)
+  fixes less_eq :: "'a \<Rightarrow> 'a \<Rightarrow> bool"  (infix "\<^bold>\<le>" 50)
+    and less :: "'a \<Rightarrow> 'a \<Rightarrow> bool"  (infix "\<^bold><" 50)
   assumes order_iff: "a \<^bold>\<le> b \<longleftrightarrow> a = a \<^bold>* b"
     and strict_order_iff: "a \<^bold>< b \<longleftrightarrow> a = a \<^bold>* b \<and> a \<noteq> b"
 begin
 
-lemma orderI:
-  "a = a \<^bold>* b \<Longrightarrow> a \<^bold>\<le> b"
+lemma orderI: "a = a \<^bold>* b \<Longrightarrow> a \<^bold>\<le> b"
   by (simp add: order_iff)
 
 lemma orderE:
   assumes "a \<^bold>\<le> b"
   obtains "a = a \<^bold>* b"
   using assms by (unfold order_iff)
 
 sublocale ordering less_eq less
 proof
   fix a b
-  show "a \<^bold>< b \<longleftrightarrow> a \<^bold>\<le> b \<and> a \<noteq> b"
+  show "a \<^bold>< b \<longleftrightarrow> a \<^bold>\<le> b \<and> a \<noteq> b" for a b
     by (simp add: order_iff strict_order_iff)
 next
   fix a
   show "a \<^bold>\<le> a"
     by (simp add: order_iff)

     by (simp add: assoc)
   with \<open>a = a \<^bold>* b\<close> [symmetric] have "a = a \<^bold>* c" by simp
   then show "a \<^bold>\<le> c" by (rule orderI)
 qed
 
-lemma cobounded1 [simp]:
-  "a \<^bold>* b \<^bold>\<le> a"
-  by (simp add: order_iff commute)  
-
-lemma cobounded2 [simp]:
-  "a \<^bold>* b \<^bold>\<le> b"
+lemma cobounded1 [simp]: "a \<^bold>* b \<^bold>\<le> a"
+  by (simp add: order_iff commute)
+
+lemma cobounded2 [simp]: "a \<^bold>* b \<^bold>\<le> b"
   by (simp add: order_iff)
 
 lemma boundedI:
   assumes "a \<^bold>\<le> b" and "a \<^bold>\<le> c"
   shows "a \<^bold>\<le> b \<^bold>* c"

 lemma boundedE:
   assumes "a \<^bold>\<le> b \<^bold>* c"
   obtains "a \<^bold>\<le> b" and "a \<^bold>\<le> c"
   using assms by (blast intro: trans cobounded1 cobounded2)
 
-lemma bounded_iff [simp]:
-  "a \<^bold>\<le> b \<^bold>* c \<longleftrightarrow> a \<^bold>\<le> b \<and> a \<^bold>\<le> c"
+lemma bounded_iff [simp]: "a \<^bold>\<le> b \<^bold>* c \<longleftrightarrow> a \<^bold>\<le> b \<and> a \<^bold>\<le> c"
   by (blast intro: boundedI elim: boundedE)
 
 lemma strict_boundedE:
   assumes "a \<^bold>< b \<^bold>* c"
   obtains "a \<^bold>< b" and "a \<^bold>< c"
   using assms by (auto simp add: commute strict_iff_order elim: orderE intro!: that)+
 
-lemma coboundedI1:
-  "a \<^bold>\<le> c \<Longrightarrow> a \<^bold>* b \<^bold>\<le> c"
+lemma coboundedI1: "a \<^bold>\<le> c \<Longrightarrow> a \<^bold>* b \<^bold>\<le> c"
   by (rule trans) auto
 
-lemma coboundedI2:
-  "b \<^bold>\<le> c \<Longrightarrow> a \<^bold>* b \<^bold>\<le> c"
+lemma coboundedI2: "b \<^bold>\<le> c \<Longrightarrow> a \<^bold>* b \<^bold>\<le> c"
   by (rule trans) auto
 
-lemma strict_coboundedI1:
-  "a \<^bold>< c \<Longrightarrow> a \<^bold>* b \<^bold>< c"
+lemma strict_coboundedI1: "a \<^bold>< c \<Longrightarrow> a \<^bold>* b \<^bold>< c"
   using irrefl
     by (auto intro: not_eq_order_implies_strict coboundedI1 strict_implies_order elim: strict_boundedE)
 
-lemma strict_coboundedI2:
-  "b \<^bold>< c \<Longrightarrow> a \<^bold>* b \<^bold>< c"
+lemma strict_coboundedI2: "b \<^bold>< c \<Longrightarrow> a \<^bold>* b \<^bold>< c"
   using strict_coboundedI1 [of b c a] by (simp add: commute)
 
 lemma mono: "a \<^bold>\<le> c \<Longrightarrow> b \<^bold>\<le> d \<Longrightarrow> a \<^bold>* b \<^bold>\<le> c \<^bold>* d"
   by (blast intro: boundedI coboundedI1 coboundedI2)
 

 subsection \<open>Syntactic infimum and supremum operations\<close>
 
 class inf =
   fixes inf :: "'a \<Rightarrow> 'a \<Rightarrow> 'a" (infixl "\<sqinter>" 70)
 
-class sup = 
+class sup =
   fixes sup :: "'a \<Rightarrow> 'a \<Rightarrow> 'a" (infixl "\<squnion>" 65)
 
 
 subsection \<open>Concrete lattices\<close>
 

   and sup_least: "y \<sqsubseteq> x \<Longrightarrow> z \<sqsubseteq> x \<Longrightarrow> y \<squnion> z \<sqsubseteq> x"
 begin
 
 text \<open>Dual lattice\<close>
 
-lemma dual_semilattice:
-  "class.semilattice_inf sup greater_eq greater"
-by (rule class.semilattice_inf.intro, rule dual_order)
-  (unfold_locales, simp_all add: sup_least)
+lemma dual_semilattice: "class.semilattice_inf sup greater_eq greater"
+  by (rule class.semilattice_inf.intro, rule dual_order)
+    (unfold_locales, simp_all add: sup_least)
 
 end
 
 class lattice = semilattice_inf + semilattice_sup
 

 subsubsection \<open>Intro and elim rules\<close>
 
 context semilattice_inf
 begin
 
-lemma le_infI1:
-  "a \<sqsubseteq> x \<Longrightarrow> a \<sqinter> b \<sqsubseteq> x"
+lemma le_infI1: "a \<sqsubseteq> x \<Longrightarrow> a \<sqinter> b \<sqsubseteq> x"
   by (rule order_trans) auto
 
-lemma le_infI2:
-  "b \<sqsubseteq> x \<Longrightarrow> a \<sqinter> b \<sqsubseteq> x"
+lemma le_infI2: "b \<sqsubseteq> x \<Longrightarrow> a \<sqinter> b \<sqsubseteq> x"
   by (rule order_trans) auto
 
 lemma le_infI: "x \<sqsubseteq> a \<Longrightarrow> x \<sqsubseteq> b \<Longrightarrow> x \<sqsubseteq> a \<sqinter> b"
   by (fact inf_greatest) (* FIXME: duplicate lemma *)
 
 lemma le_infE: "x \<sqsubseteq> a \<sqinter> b \<Longrightarrow> (x \<sqsubseteq> a \<Longrightarrow> x \<sqsubseteq> b \<Longrightarrow> P) \<Longrightarrow> P"
   by (blast intro: order_trans inf_le1 inf_le2)
 
-lemma le_inf_iff:
-  "x \<sqsubseteq> y \<sqinter> z \<longleftrightarrow> x \<sqsubseteq> y \<and> x \<sqsubseteq> z"
+lemma le_inf_iff: "x \<sqsubseteq> y \<sqinter> z \<longleftrightarrow> x \<sqsubseteq> y \<and> x \<sqsubseteq> z"
   by (blast intro: le_infI elim: le_infE)
 
-lemma le_iff_inf:
-  "x \<sqsubseteq> y \<longleftrightarrow> x \<sqinter> y = x"
+lemma le_iff_inf: "x \<sqsubseteq> y \<longleftrightarrow> x \<sqinter> y = x"
   by (auto intro: le_infI1 antisym dest: eq_iff [THEN iffD1] simp add: le_inf_iff)
 
 lemma inf_mono: "a \<sqsubseteq> c \<Longrightarrow> b \<sqsubseteq> d \<Longrightarrow> a \<sqinter> b \<sqsubseteq> c \<sqinter> d"
   by (fast intro: inf_greatest le_infI1 le_infI2)
 
-lemma mono_inf:
-  fixes f :: "'a \<Rightarrow> 'b::semilattice_inf"
-  shows "mono f \<Longrightarrow> f (A \<sqinter> B) \<sqsubseteq> f A \<sqinter> f B"
+lemma mono_inf: "mono f \<Longrightarrow> f (A \<sqinter> B) \<sqsubseteq> f A \<sqinter> f B" for f :: "'a \<Rightarrow> 'b::semilattice_inf"
   by (auto simp add: mono_def intro: Lattices.inf_greatest)
 
 end
 
 context semilattice_sup
 begin
 
-lemma le_supI1:
-  "x \<sqsubseteq> a \<Longrightarrow> x \<sqsubseteq> a \<squnion> b"
+lemma le_supI1: "x \<sqsubseteq> a \<Longrightarrow> x \<sqsubseteq> a \<squnion> b"
   by (rule order_trans) auto
 
-lemma le_supI2:
-  "x \<sqsubseteq> b \<Longrightarrow> x \<sqsubseteq> a \<squnion> b"
-  by (rule order_trans) auto 
-
-lemma le_supI:
-  "a \<sqsubseteq> x \<Longrightarrow> b \<sqsubseteq> x \<Longrightarrow> a \<squnion> b \<sqsubseteq> x"
+lemma le_supI2: "x \<sqsubseteq> b \<Longrightarrow> x \<sqsubseteq> a \<squnion> b"
+  by (rule order_trans) auto
+
+lemma le_supI: "a \<sqsubseteq> x \<Longrightarrow> b \<sqsubseteq> x \<Longrightarrow> a \<squnion> b \<sqsubseteq> x"
   by (fact sup_least) (* FIXME: duplicate lemma *)
 
-lemma le_supE:
-  "a \<squnion> b \<sqsubseteq> x \<Longrightarrow> (a \<sqsubseteq> x \<Longrightarrow> b \<sqsubseteq> x \<Longrightarrow> P) \<Longrightarrow> P"
+lemma le_supE: "a \<squnion> b \<sqsubseteq> x \<Longrightarrow> (a \<sqsubseteq> x \<Longrightarrow> b \<sqsubseteq> x \<Longrightarrow> P) \<Longrightarrow> P"
   by (blast intro: order_trans sup_ge1 sup_ge2)
 
-lemma le_sup_iff:
-  "x \<squnion> y \<sqsubseteq> z \<longleftrightarrow> x \<sqsubseteq> z \<and> y \<sqsubseteq> z"
+lemma le_sup_iff: "x \<squnion> y \<sqsubseteq> z \<longleftrightarrow> x \<sqsubseteq> z \<and> y \<sqsubseteq> z"
   by (blast intro: le_supI elim: le_supE)
 
-lemma le_iff_sup:
-  "x \<sqsubseteq> y \<longleftrightarrow> x \<squnion> y = y"
+lemma le_iff_sup: "x \<sqsubseteq> y \<longleftrightarrow> x \<squnion> y = y"
   by (auto intro: le_supI2 antisym dest: eq_iff [THEN iffD1] simp add: le_sup_iff)
 
 lemma sup_mono: "a \<sqsubseteq> c \<Longrightarrow> b \<sqsubseteq> d \<Longrightarrow> a \<squnion> b \<sqsubseteq> c \<squnion> d"
   by (fast intro: sup_least le_supI1 le_supI2)
 
-lemma mono_sup:
-  fixes f :: "'a \<Rightarrow> 'b::semilattice_sup"
-  shows "mono f \<Longrightarrow> f A \<squnion> f B \<sqsubseteq> f (A \<squnion> B)"
+lemma mono_sup: "mono f \<Longrightarrow> f A \<squnion> f B \<sqsubseteq> f (A \<squnion> B)" for f :: "'a \<Rightarrow> 'b::semilattice_sup"
   by (auto simp add: mono_def intro: Lattices.sup_least)
 
 end
 
 

 lemma inf_absorb1: "x \<sqsubseteq> y \<Longrightarrow> x \<sqinter> y = x"
   by (rule antisym) auto
 
 lemma inf_absorb2: "y \<sqsubseteq> x \<Longrightarrow> x \<sqinter> y = y"
   by (rule antisym) auto
- 
+
 lemmas inf_aci = inf_commute inf_assoc inf_left_commute inf_left_idem
 
 end
 
 context semilattice_sup

 end
 
 context lattice
 begin
 
-lemma dual_lattice:
-  "class.lattice sup (op \<ge>) (op >) inf"
+lemma dual_lattice: "class.lattice sup (op \<ge>) (op >) inf"
   by (rule class.lattice.intro, rule dual_semilattice, rule class.semilattice_sup.intro, rule dual_order)
     (unfold_locales, auto)
 
 lemma inf_sup_absorb [simp]: "x \<sqinter> (x \<squnion> y) = x"
   by (blast intro: antisym inf_le1 inf_greatest sup_ge1)

   by (auto intro: le_infI1 le_infI2 le_supI1 le_supI2)
 
 lemma distrib_inf_le: "(x \<sqinter> y) \<squnion> (x \<sqinter> z) \<sqsubseteq> x \<sqinter> (y \<squnion> z)"
   by (auto intro: le_infI1 le_infI2 le_supI1 le_supI2)
 
-text\<open>If you have one of them, you have them all.\<close>
+text \<open>If you have one of them, you have them all.\<close>
 
 lemma distrib_imp1:
-assumes D: "!!x y z. x \<sqinter> (y \<squnion> z) = (x \<sqinter> y) \<squnion> (x \<sqinter> z)"
-shows "x \<squnion> (y \<sqinter> z) = (x \<squnion> y) \<sqinter> (x \<squnion> z)"
+  assumes distrib: "\<And>x y z. x \<sqinter> (y \<squnion> z) = (x \<sqinter> y) \<squnion> (x \<sqinter> z)"
+  shows "x \<squnion> (y \<sqinter> z) = (x \<squnion> y) \<sqinter> (x \<squnion> z)"
 proof-
-  have "x \<squnion> (y \<sqinter> z) = (x \<squnion> (x \<sqinter> z)) \<squnion> (y \<sqinter> z)" by simp
+  have "x \<squnion> (y \<sqinter> z) = (x \<squnion> (x \<sqinter> z)) \<squnion> (y \<sqinter> z)"
+    by simp
   also have "\<dots> = x \<squnion> (z \<sqinter> (x \<squnion> y))"
-    by (simp add: D inf_commute sup_assoc del: sup_inf_absorb)
+    by (simp add: distrib inf_commute sup_assoc del: sup_inf_absorb)
   also have "\<dots> = ((x \<squnion> y) \<sqinter> x) \<squnion> ((x \<squnion> y) \<sqinter> z)"
-    by(simp add: inf_commute)
-  also have "\<dots> = (x \<squnion> y) \<sqinter> (x \<squnion> z)" by(simp add:D)
+    by (simp add: inf_commute)
+  also have "\<dots> = (x \<squnion> y) \<sqinter> (x \<squnion> z)" by(simp add:distrib)
   finally show ?thesis .
 qed
 
 lemma distrib_imp2:
-assumes D: "!!x y z. x \<squnion> (y \<sqinter> z) = (x \<squnion> y) \<sqinter> (x \<squnion> z)"
-shows "x \<sqinter> (y \<squnion> z) = (x \<sqinter> y) \<squnion> (x \<sqinter> z)"
+  assumes distrib: "\<And>x y z. x \<squnion> (y \<sqinter> z) = (x \<squnion> y) \<sqinter> (x \<squnion> z)"
+  shows "x \<sqinter> (y \<squnion> z) = (x \<sqinter> y) \<squnion> (x \<sqinter> z)"
 proof-
-  have "x \<sqinter> (y \<squnion> z) = (x \<sqinter> (x \<squnion> z)) \<sqinter> (y \<squnion> z)" by simp
+  have "x \<sqinter> (y \<squnion> z) = (x \<sqinter> (x \<squnion> z)) \<sqinter> (y \<squnion> z)"
+    by simp
   also have "\<dots> = x \<sqinter> (z \<squnion> (x \<sqinter> y))"
-    by (simp add: D sup_commute inf_assoc del: inf_sup_absorb)
+    by (simp add: distrib sup_commute inf_assoc del: inf_sup_absorb)
   also have "\<dots> = ((x \<sqinter> y) \<squnion> x) \<sqinter> ((x \<sqinter> y) \<squnion> z)"
-    by(simp add: sup_commute)
-  also have "\<dots> = (x \<sqinter> y) \<squnion> (x \<sqinter> z)" by(simp add:D)
+    by (simp add: sup_commute)
+  also have "\<dots> = (x \<sqinter> y) \<squnion> (x \<sqinter> z)" by (simp add:distrib)
   finally show ?thesis .
 qed
 
 end
 
+
 subsubsection \<open>Strict order\<close>
 
 context semilattice_inf
 begin
 
-lemma less_infI1:
-  "a \<sqsubset> x \<Longrightarrow> a \<sqinter> b \<sqsubset> x"
+lemma less_infI1: "a \<sqsubset> x \<Longrightarrow> a \<sqinter> b \<sqsubset> x"
   by (auto simp add: less_le inf_absorb1 intro: le_infI1)
 
-lemma less_infI2:
-  "b \<sqsubset> x \<Longrightarrow> a \<sqinter> b \<sqsubset> x"
+lemma less_infI2: "b \<sqsubset> x \<Longrightarrow> a \<sqinter> b \<sqsubset> x"
   by (auto simp add: less_le inf_absorb2 intro: le_infI2)
 
 end
 
 context semilattice_sup
 begin
 
-lemma less_supI1:
-  "x \<sqsubset> a \<Longrightarrow> x \<sqsubset> a \<squnion> b"
+lemma less_supI1: "x \<sqsubset> a \<Longrightarrow> x \<sqsubset> a \<squnion> b"
   using dual_semilattice
   by (rule semilattice_inf.less_infI1)
 
-lemma less_supI2:
-  "x \<sqsubset> b \<Longrightarrow> x \<sqsubset> a \<squnion> b"
+lemma less_supI2: "x \<sqsubset> b \<Longrightarrow> x \<sqsubset> a \<squnion> b"
   using dual_semilattice
   by (rule semilattice_inf.less_infI2)
 
 end
 

   assumes sup_inf_distrib1: "x \<squnion> (y \<sqinter> z) = (x \<squnion> y) \<sqinter> (x \<squnion> z)"
 
 context distrib_lattice
 begin
 
-lemma sup_inf_distrib2:
-  "(y \<sqinter> z) \<squnion> x = (y \<squnion> x) \<sqinter> (z \<squnion> x)"
+lemma sup_inf_distrib2: "(y \<sqinter> z) \<squnion> x = (y \<squnion> x) \<sqinter> (z \<squnion> x)"
   by (simp add: sup_commute sup_inf_distrib1)
 
-lemma inf_sup_distrib1:
-  "x \<sqinter> (y \<squnion> z) = (x \<sqinter> y) \<squnion> (x \<sqinter> z)"
+lemma inf_sup_distrib1: "x \<sqinter> (y \<squnion> z) = (x \<sqinter> y) \<squnion> (x \<sqinter> z)"
   by (rule distrib_imp2 [OF sup_inf_distrib1])
 
-lemma inf_sup_distrib2:
-  "(y \<squnion> z) \<sqinter> x = (y \<sqinter> x) \<squnion> (z \<sqinter> x)"
+lemma inf_sup_distrib2: "(y \<squnion> z) \<sqinter> x = (y \<sqinter> x) \<squnion> (z \<sqinter> x)"
   by (simp add: inf_commute inf_sup_distrib1)
 
-lemma dual_distrib_lattice:
-  "class.distrib_lattice sup (op \<ge>) (op >) inf"
+lemma dual_distrib_lattice: "class.distrib_lattice sup (op \<ge>) (op >) inf"
   by (rule class.distrib_lattice.intro, rule dual_lattice)
     (unfold_locales, fact inf_sup_distrib1)
 
-lemmas sup_inf_distrib =
-  sup_inf_distrib1 sup_inf_distrib2
-
-lemmas inf_sup_distrib =
-  inf_sup_distrib1 inf_sup_distrib2
-
-lemmas distrib =
-  sup_inf_distrib1 sup_inf_distrib2 inf_sup_distrib1 inf_sup_distrib2
+lemmas sup_inf_distrib = sup_inf_distrib1 sup_inf_distrib2
+
+lemmas inf_sup_distrib = inf_sup_distrib1 inf_sup_distrib2
+
+lemmas distrib = sup_inf_distrib1 sup_inf_distrib2 inf_sup_distrib1 inf_sup_distrib2
 
 end
 
 
 subsection \<open>Bounded lattices and boolean algebras\<close>

 begin
 
 sublocale inf_top: semilattice_neutr inf top
   + inf_top: semilattice_neutr_order inf top less_eq less
 proof
-  fix x
-  show "x \<sqinter> \<top> = x"
+  show "x \<sqinter> \<top> = x" for x
     by (rule inf_absorb1) simp
 qed
 
 end
 

 begin
 
 sublocale sup_bot: semilattice_neutr sup bot
   + sup_bot: semilattice_neutr_order sup bot greater_eq greater
 proof
-  fix x
-  show "x \<squnion> \<bottom> = x"
+  show "x \<squnion> \<bottom> = x" for x
     by (rule sup_absorb1) simp
 qed
 
 end
 
 class bounded_lattice_bot = lattice + order_bot
 begin
 
 subclass bounded_semilattice_sup_bot ..
 
-lemma inf_bot_left [simp]:
-  "\<bottom> \<sqinter> x = \<bottom>"
+lemma inf_bot_left [simp]: "\<bottom> \<sqinter> x = \<bottom>"
   by (rule inf_absorb1) simp
 
-lemma inf_bot_right [simp]:
-  "x \<sqinter> \<bottom> = \<bottom>"
+lemma inf_bot_right [simp]: "x \<sqinter> \<bottom> = \<bottom>"
   by (rule inf_absorb2) simp
 
-lemma sup_bot_left:
-  "\<bottom> \<squnion> x = x"
+lemma sup_bot_left: "\<bottom> \<squnion> x = x"
   by (fact sup_bot.left_neutral)
 
-lemma sup_bot_right:
-  "x \<squnion> \<bottom> = x"
+lemma sup_bot_right: "x \<squnion> \<bottom> = x"
   by (fact sup_bot.right_neutral)
 
-lemma sup_eq_bot_iff [simp]:
-  "x \<squnion> y = \<bottom> \<longleftrightarrow> x = \<bottom> \<and> y = \<bottom>"
+lemma sup_eq_bot_iff [simp]: "x \<squnion> y = \<bottom> \<longleftrightarrow> x = \<bottom> \<and> y = \<bottom>"
   by (simp add: eq_iff)
 
-lemma bot_eq_sup_iff [simp]:
-  "\<bottom> = x \<squnion> y \<longleftrightarrow> x = \<bottom> \<and> y = \<bottom>"
+lemma bot_eq_sup_iff [simp]: "\<bottom> = x \<squnion> y \<longleftrightarrow> x = \<bottom> \<and> y = \<bottom>"
   by (simp add: eq_iff)
 
 end
 
 class bounded_lattice_top = lattice + order_top
 begin
 
 subclass bounded_semilattice_inf_top ..
 
-lemma sup_top_left [simp]:
-  "\<top> \<squnion> x = \<top>"
+lemma sup_top_left [simp]: "\<top> \<squnion> x = \<top>"
   by (rule sup_absorb1) simp
 
-lemma sup_top_right [simp]:
-  "x \<squnion> \<top> = \<top>"
+lemma sup_top_right [simp]: "x \<squnion> \<top> = \<top>"
   by (rule sup_absorb2) simp
 
-lemma inf_top_left:
-  "\<top> \<sqinter> x = x"
+lemma inf_top_left: "\<top> \<sqinter> x = x"
   by (fact inf_top.left_neutral)
 
-lemma inf_top_right:
-  "x \<sqinter> \<top> = x"
+lemma inf_top_right: "x \<sqinter> \<top> = x"
   by (fact inf_top.right_neutral)
 
-lemma inf_eq_top_iff [simp]:
-  "x \<sqinter> y = \<top> \<longleftrightarrow> x = \<top> \<and> y = \<top>"
+lemma inf_eq_top_iff [simp]: "x \<sqinter> y = \<top> \<longleftrightarrow> x = \<top> \<and> y = \<top>"
   by (simp add: eq_iff)
 
 end
 
 class bounded_lattice = lattice + order_bot + order_top
 begin
 
 subclass bounded_lattice_bot ..
 subclass bounded_lattice_top ..
 
-lemma dual_bounded_lattice:
-  "class.bounded_lattice sup greater_eq greater inf \<top> \<bottom>"
+lemma dual_bounded_lattice: "class.bounded_lattice sup greater_eq greater inf \<top> \<bottom>"
   by unfold_locales (auto simp add: less_le_not_le)
 
 end
 
 class boolean_algebra = distrib_lattice + bounded_lattice + minus + uminus +

 lemma dual_boolean_algebra:
   "class.boolean_algebra (\<lambda>x y. x \<squnion> - y) uminus sup greater_eq greater inf \<top> \<bottom>"
   by (rule class.boolean_algebra.intro, rule dual_bounded_lattice, rule dual_distrib_lattice)
     (unfold_locales, auto simp add: inf_compl_bot sup_compl_top diff_eq)
 
-lemma compl_inf_bot [simp]:
-  "- x \<sqinter> x = \<bottom>"
+lemma compl_inf_bot [simp]: "- x \<sqinter> x = \<bottom>"
   by (simp add: inf_commute inf_compl_bot)
 
-lemma compl_sup_top [simp]:
-  "- x \<squnion> x = \<top>"
+lemma compl_sup_top [simp]: "- x \<squnion> x = \<top>"
   by (simp add: sup_commute sup_compl_top)
 
 lemma compl_unique:
   assumes "x \<sqinter> y = \<bottom>"
     and "x \<squnion> y = \<top>"

   then have "- x \<sqinter> \<top> = y \<sqinter> \<top>"
     using sup_compl_top assms(2) by simp
   then show "- x = y" by simp
 qed
 
-lemma double_compl [simp]:
-  "- (- x) = x"
+lemma double_compl [simp]: "- (- x) = x"
   using compl_inf_bot compl_sup_top by (rule compl_unique)
 
-lemma compl_eq_compl_iff [simp]:
-  "- x = - y \<longleftrightarrow> x = y"
+lemma compl_eq_compl_iff [simp]: "- x = - y \<longleftrightarrow> x = y"
 proof
   assume "- x = - y"
   then have "- (- x) = - (- y)" by (rule arg_cong)
   then show "x = y" by simp
 next
   assume "x = y"
   then show "- x = - y" by simp
 qed
 
-lemma compl_bot_eq [simp]:
-  "- \<bottom> = \<top>"
+lemma compl_bot_eq [simp]: "- \<bottom> = \<top>"
 proof -
   from sup_compl_top have "\<bottom> \<squnion> - \<bottom> = \<top>" .
   then show ?thesis by simp
 qed
 
-lemma compl_top_eq [simp]:
-  "- \<top> = \<bottom>"
+lemma compl_top_eq [simp]: "- \<top> = \<bottom>"
 proof -
   from inf_compl_bot have "\<top> \<sqinter> - \<top> = \<bottom>" .
   then show ?thesis by simp
 qed
 
-lemma compl_inf [simp]:
-  "- (x \<sqinter> y) = - x \<squnion> - y"
+lemma compl_inf [simp]: "- (x \<sqinter> y) = - x \<squnion> - y"
 proof (rule compl_unique)
   have "(x \<sqinter> y) \<sqinter> (- x \<squnion> - y) = (y \<sqinter> (x \<sqinter> - x)) \<squnion> (x \<sqinter> (y \<sqinter> - y))"
     by (simp only: inf_sup_distrib inf_aci)
   then show "(x \<sqinter> y) \<sqinter> (- x \<squnion> - y) = \<bottom>"
     by (simp add: inf_compl_bot)

     by (simp only: sup_inf_distrib sup_aci)
   then show "(x \<sqinter> y) \<squnion> (- x \<squnion> - y) = \<top>"
     by (simp add: sup_compl_top)
 qed
 
-lemma compl_sup [simp]:
-  "- (x \<squnion> y) = - x \<sqinter> - y"
+lemma compl_sup [simp]: "- (x \<squnion> y) = - x \<sqinter> - y"
   using dual_boolean_algebra
   by (rule boolean_algebra.compl_inf)
 
 lemma compl_mono:
-  "x \<sqsubseteq> y \<Longrightarrow> - y \<sqsubseteq> - x"
+  assumes "x \<sqsubseteq> y"
+  shows "- y \<sqsubseteq> - x"
 proof -
-  assume "x \<sqsubseteq> y"
-  then have "x \<squnion> y = y" by (simp only: le_iff_sup)
+  from assms have "x \<squnion> y = y" by (simp only: le_iff_sup)
   then have "- (x \<squnion> y) = - y" by simp
   then have "- x \<sqinter> - y = - y" by simp
   then have "- y \<sqinter> - x = - y" by (simp only: inf_commute)
-  then show "- y \<sqsubseteq> - x" by (simp only: le_iff_inf)
-qed
-
-lemma compl_le_compl_iff [simp]:
-  "- x \<sqsubseteq> - y \<longleftrightarrow> y \<sqsubseteq> x"
+  then show ?thesis by (simp only: le_iff_inf)
+qed
+
+lemma compl_le_compl_iff [simp]: "- x \<sqsubseteq> - y \<longleftrightarrow> y \<sqsubseteq> x"
   by (auto dest: compl_mono)
 
 lemma compl_le_swap1:
-  assumes "y \<sqsubseteq> - x" shows "x \<sqsubseteq> -y"
+  assumes "y \<sqsubseteq> - x"
+  shows "x \<sqsubseteq> -y"
 proof -
   from assms have "- (- x) \<sqsubseteq> - y" by (simp only: compl_le_compl_iff)
   then show ?thesis by simp
 qed
 
 lemma compl_le_swap2:
-  assumes "- y \<sqsubseteq> x" shows "- x \<sqsubseteq> y"
+  assumes "- y \<sqsubseteq> x"
+  shows "- x \<sqsubseteq> y"
 proof -
   from assms have "- x \<sqsubseteq> - (- y)" by (simp only: compl_le_compl_iff)
   then show ?thesis by simp
 qed
 
-lemma compl_less_compl_iff: (* TODO: declare [simp] ? *)
-  "- x \<sqsubset> - y \<longleftrightarrow> y \<sqsubset> x"
+lemma compl_less_compl_iff: "- x \<sqsubset> - y \<longleftrightarrow> y \<sqsubset> x"  (* TODO: declare [simp] ? *)
   by (auto simp add: less_le)
 
 lemma compl_less_swap1:
-  assumes "y \<sqsubset> - x" shows "x \<sqsubset> - y"
+  assumes "y \<sqsubset> - x"
+  shows "x \<sqsubset> - y"
 proof -
   from assms have "- (- x) \<sqsubset> - y" by (simp only: compl_less_compl_iff)
   then show ?thesis by simp
 qed
 
 lemma compl_less_swap2:
-  assumes "- y \<sqsubset> x" shows "- x \<sqsubset> y"
+  assumes "- y \<sqsubset> x"
+  shows "- x \<sqsubset> y"
 proof -
   from assms have "- x \<sqsubset> - (- y)" by (simp only: compl_less_compl_iff)
   then show ?thesis by simp
 qed
 
 lemma sup_cancel_left1: "sup (sup x a) (sup (- x) b) = top"
-by(simp add: inf_sup_aci sup_compl_top)
+  by (simp add: inf_sup_aci sup_compl_top)
 
 lemma sup_cancel_left2: "sup (sup (- x) a) (sup x b) = top"
-by(simp add: inf_sup_aci sup_compl_top)
+  by (simp add: inf_sup_aci sup_compl_top)
 
 lemma inf_cancel_left1: "inf (inf x a) (inf (- x) b) = bot"
-by(simp add: inf_sup_aci inf_compl_bot)
+  by (simp add: inf_sup_aci inf_compl_bot)
 
 lemma inf_cancel_left2: "inf (inf (- x) a) (inf x b) = bot"
-by(simp add: inf_sup_aci inf_compl_bot)
-
-declare inf_compl_bot [simp] sup_compl_top [simp]
+  by (simp add: inf_sup_aci inf_compl_bot)
+
+declare inf_compl_bot [simp] and sup_compl_top [simp]
 
 lemma sup_compl_top_left1 [simp]: "sup (- x) (sup x y) = top"
-by(simp add: sup_assoc[symmetric])
+  by (simp add: sup_assoc[symmetric])
 
 lemma sup_compl_top_left2 [simp]: "sup x (sup (- x) y) = top"
-using sup_compl_top_left1[of "- x" y] by simp
+  using sup_compl_top_left1[of "- x" y] by simp
 
 lemma inf_compl_bot_left1 [simp]: "inf (- x) (inf x y) = bot"
-by(simp add: inf_assoc[symmetric])
+  by (simp add: inf_assoc[symmetric])
 
 lemma inf_compl_bot_left2 [simp]: "inf x (inf (- x) y) = bot"
-using inf_compl_bot_left1[of "- x" y] by simp
+  using inf_compl_bot_left1[of "- x" y] by simp
 
 lemma inf_compl_bot_right [simp]: "inf x (inf y (- x)) = bot"
-by(subst inf_left_commute) simp
+  by (subst inf_left_commute) simp
 
 end
 
 ML_file "Tools/boolean_algebra_cancel.ML"
 
 simproc_setup boolean_algebra_cancel_sup ("sup a b::'a::boolean_algebra") =
   \<open>fn phi => fn ss => try Boolean_Algebra_Cancel.cancel_sup_conv\<close>
 
 simproc_setup boolean_algebra_cancel_inf ("inf a b::'a::boolean_algebra") =
   \<open>fn phi => fn ss => try Boolean_Algebra_Cancel.cancel_inf_conv\<close>
+
 
 subsection \<open>\<open>min/max\<close> as special case of lattice\<close>
 
 context linorder
 begin
 
 sublocale min: semilattice_order min less_eq less
   + max: semilattice_order max greater_eq greater
   by standard (auto simp add: min_def max_def)
 
-lemma min_le_iff_disj:
-  "min x y \<le> z \<longleftrightarrow> x \<le> z \<or> y \<le> z"
+lemma min_le_iff_disj: "min x y \<le> z \<longleftrightarrow> x \<le> z \<or> y \<le> z"
   unfolding min_def using linear by (auto intro: order_trans)
 
-lemma le_max_iff_disj:
-  "z \<le> max x y \<longleftrightarrow> z \<le> x \<or> z \<le> y"
+lemma le_max_iff_disj: "z \<le> max x y \<longleftrightarrow> z \<le> x \<or> z \<le> y"
   unfolding max_def using linear by (auto intro: order_trans)
 
-lemma min_less_iff_disj:
-  "min x y < z \<longleftrightarrow> x < z \<or> y < z"
+lemma min_less_iff_disj: "min x y < z \<longleftrightarrow> x < z \<or> y < z"
   unfolding min_def le_less using less_linear by (auto intro: less_trans)
 
-lemma less_max_iff_disj:
-  "z < max x y \<longleftrightarrow> z < x \<or> z < y"
+lemma less_max_iff_disj: "z < max x y \<longleftrightarrow> z < x \<or> z < y"
   unfolding max_def le_less using less_linear by (auto intro: less_trans)
 
-lemma min_less_iff_conj [simp]:
-  "z < min x y \<longleftrightarrow> z < x \<and> z < y"
+lemma min_less_iff_conj [simp]: "z < min x y \<longleftrightarrow> z < x \<and> z < y"
   unfolding min_def le_less using less_linear by (auto intro: less_trans)
 
-lemma max_less_iff_conj [simp]:
-  "max x y < z \<longleftrightarrow> x < z \<and> y < z"
+lemma max_less_iff_conj [simp]: "max x y < z \<longleftrightarrow> x < z \<and> y < z"
   unfolding max_def le_less using less_linear by (auto intro: less_trans)
 
-lemma min_max_distrib1:
-  "min (max b c) a = max (min b a) (min c a)"
+lemma min_max_distrib1: "min (max b c) a = max (min b a) (min c a)"
   by (auto simp add: min_def max_def not_le dest: le_less_trans less_trans intro: antisym)
 
-lemma min_max_distrib2:
-  "min a (max b c) = max (min a b) (min a c)"
+lemma min_max_distrib2: "min a (max b c) = max (min a b) (min a c)"
   by (auto simp add: min_def max_def not_le dest: le_less_trans less_trans intro: antisym)
 
-lemma max_min_distrib1:
-  "max (min b c) a = min (max b a) (max c a)"
+lemma max_min_distrib1: "max (min b c) a = min (max b a) (max c a)"
   by (auto simp add: min_def max_def not_le dest: le_less_trans less_trans intro: antisym)
 
-lemma max_min_distrib2:
-  "max a (min b c) = min (max a b) (max a c)"
+lemma max_min_distrib2: "max a (min b c) = min (max a b) (max a c)"
   by (auto simp add: min_def max_def not_le dest: le_less_trans less_trans intro: antisym)
 
 lemmas min_max_distribs = min_max_distrib1 min_max_distrib2 max_min_distrib1 max_min_distrib2
 
-lemma split_min [no_atp]:
-  "P (min i j) \<longleftrightarrow> (i \<le> j \<longrightarrow> P i) \<and> (\<not> i \<le> j \<longrightarrow> P j)"
+lemma split_min [no_atp]: "P (min i j) \<longleftrightarrow> (i \<le> j \<longrightarrow> P i) \<and> (\<not> i \<le> j \<longrightarrow> P j)"
   by (simp add: min_def)
 
-lemma split_max [no_atp]:
-  "P (max i j) \<longleftrightarrow> (i \<le> j \<longrightarrow> P j) \<and> (\<not> i \<le> j \<longrightarrow> P i)"
+lemma split_max [no_atp]: "P (max i j) \<longleftrightarrow> (i \<le> j \<longrightarrow> P j) \<and> (\<not> i \<le> j \<longrightarrow> P i)"
   by (simp add: max_def)
 
-lemma min_of_mono:
-  fixes f :: "'a \<Rightarrow> 'b::linorder"
-  shows "mono f \<Longrightarrow> min (f m) (f n) = f (min m n)"
+lemma min_of_mono: "mono f \<Longrightarrow> min (f m) (f n) = f (min m n)" for f :: "'a \<Rightarrow> 'b::linorder"
   by (auto simp: mono_def Orderings.min_def min_def intro: Orderings.antisym)
 
-lemma max_of_mono:
-  fixes f :: "'a \<Rightarrow> 'b::linorder"
-  shows "mono f \<Longrightarrow> max (f m) (f n) = f (max m n)"
+lemma max_of_mono: "mono f \<Longrightarrow> max (f m) (f n) = f (max m n)" for f :: "'a \<Rightarrow> 'b::linorder"
   by (auto simp: mono_def Orderings.max_def max_def intro: Orderings.antisym)
 
 end
 
 lemma inf_min: "inf = (min :: 'a::{semilattice_inf,linorder} \<Rightarrow> 'a \<Rightarrow> 'a)"

 
 
 subsection \<open>Uniqueness of inf and sup\<close>
 
 lemma (in semilattice_inf) inf_unique:
-  fixes f (infixl "\<triangle>" 70)
-  assumes le1: "\<And>x y. x \<triangle> y \<sqsubseteq> x" and le2: "\<And>x y. x \<triangle> y \<sqsubseteq> y"
-  and greatest: "\<And>x y z. x \<sqsubseteq> y \<Longrightarrow> x \<sqsubseteq> z \<Longrightarrow> x \<sqsubseteq> y \<triangle> z"
+  fixes f  (infixl "\<triangle>" 70)
+  assumes le1: "\<And>x y. x \<triangle> y \<sqsubseteq> x"
+    and le2: "\<And>x y. x \<triangle> y \<sqsubseteq> y"
+    and greatest: "\<And>x y z. x \<sqsubseteq> y \<Longrightarrow> x \<sqsubseteq> z \<Longrightarrow> x \<sqsubseteq> y \<triangle> z"
   shows "x \<sqinter> y = x \<triangle> y"
 proof (rule antisym)
-  show "x \<triangle> y \<sqsubseteq> x \<sqinter> y" by (rule le_infI) (rule le1, rule le2)
-next
-  have leI: "\<And>x y z. x \<sqsubseteq> y \<Longrightarrow> x \<sqsubseteq> z \<Longrightarrow> x \<sqsubseteq> y \<triangle> z" by (blast intro: greatest)
-  show "x \<sqinter> y \<sqsubseteq> x \<triangle> y" by (rule leI) simp_all
+  show "x \<triangle> y \<sqsubseteq> x \<sqinter> y"
+    by (rule le_infI) (rule le1, rule le2)
+  have leI: "\<And>x y z. x \<sqsubseteq> y \<Longrightarrow> x \<sqsubseteq> z \<Longrightarrow> x \<sqsubseteq> y \<triangle> z"
+    by (blast intro: greatest)
+  show "x \<sqinter> y \<sqsubseteq> x \<triangle> y"
+    by (rule leI) simp_all
 qed
 
 lemma (in semilattice_sup) sup_unique:
-  fixes f (infixl "\<nabla>" 70)
-  assumes ge1 [simp]: "\<And>x y. x \<sqsubseteq> x \<nabla> y" and ge2: "\<And>x y. y \<sqsubseteq> x \<nabla> y"
-  and least: "\<And>x y z. y \<sqsubseteq> x \<Longrightarrow> z \<sqsubseteq> x \<Longrightarrow> y \<nabla> z \<sqsubseteq> x"
+  fixes f  (infixl "\<nabla>" 70)
+  assumes ge1 [simp]: "\<And>x y. x \<sqsubseteq> x \<nabla> y"
+    and ge2: "\<And>x y. y \<sqsubseteq> x \<nabla> y"
+    and least: "\<And>x y z. y \<sqsubseteq> x \<Longrightarrow> z \<sqsubseteq> x \<Longrightarrow> y \<nabla> z \<sqsubseteq> x"
   shows "x \<squnion> y = x \<nabla> y"
 proof (rule antisym)
-  show "x \<squnion> y \<sqsubseteq> x \<nabla> y" by (rule le_supI) (rule ge1, rule ge2)
-next
-  have leI: "\<And>x y z. x \<sqsubseteq> z \<Longrightarrow> y \<sqsubseteq> z \<Longrightarrow> x \<nabla> y \<sqsubseteq> z" by (blast intro: least)
-  show "x \<nabla> y \<sqsubseteq> x \<squnion> y" by (rule leI) simp_all
+  show "x \<squnion> y \<sqsubseteq> x \<nabla> y"
+    by (rule le_supI) (rule ge1, rule ge2)
+  have leI: "\<And>x y z. x \<sqsubseteq> z \<Longrightarrow> y \<sqsubseteq> z \<Longrightarrow> x \<nabla> y \<sqsubseteq> z"
+    by (blast intro: least)
+  show "x \<nabla> y \<sqsubseteq> x \<squnion> y"
+    by (rule leI) simp_all
 qed
 
 
 subsection \<open>Lattice on @{typ bool}\<close>
 
 instantiation bool :: boolean_algebra
 begin
 
-definition
-  bool_Compl_def [simp]: "uminus = Not"
-
-definition
-  bool_diff_def [simp]: "A - B \<longleftrightarrow> A \<and> \<not> B"
-
-definition
-  [simp]: "P \<sqinter> Q \<longleftrightarrow> P \<and> Q"
-
-definition
-  [simp]: "P \<squnion> Q \<longleftrightarrow> P \<or> Q"
-
-instance proof
-qed auto
-
-end
-
-lemma sup_boolI1:
-  "P \<Longrightarrow> P \<squnion> Q"
+definition bool_Compl_def [simp]: "uminus = Not"
+
+definition bool_diff_def [simp]: "A - B \<longleftrightarrow> A \<and> \<not> B"
+
+definition [simp]: "P \<sqinter> Q \<longleftrightarrow> P \<and> Q"
+
+definition [simp]: "P \<squnion> Q \<longleftrightarrow> P \<or> Q"
+
+instance by standard auto
+
+end
+
+lemma sup_boolI1: "P \<Longrightarrow> P \<squnion> Q"
   by simp
 
-lemma sup_boolI2:
-  "Q \<Longrightarrow> P \<squnion> Q"
+lemma sup_boolI2: "Q \<Longrightarrow> P \<squnion> Q"
   by simp
 
-lemma sup_boolE:
-  "P \<squnion> Q \<Longrightarrow> (P \<Longrightarrow> R) \<Longrightarrow> (Q \<Longrightarrow> R) \<Longrightarrow> R"
+lemma sup_boolE: "P \<squnion> Q \<Longrightarrow> (P \<Longrightarrow> R) \<Longrightarrow> (Q \<Longrightarrow> R) \<Longrightarrow> R"
   by auto
 
 
 subsection \<open>Lattice on @{typ "_ \<Rightarrow> _"}\<close>
 
 instantiation "fun" :: (type, semilattice_sup) semilattice_sup
 begin
 
-definition
-  "f \<squnion> g = (\<lambda>x. f x \<squnion> g x)"
-
-lemma sup_apply [simp, code]:
-  "(f \<squnion> g) x = f x \<squnion> g x"
+definition "f \<squnion> g = (\<lambda>x. f x \<squnion> g x)"
+
+lemma sup_apply [simp, code]: "(f \<squnion> g) x = f x \<squnion> g x"
   by (simp add: sup_fun_def)
 
-instance proof
-qed (simp_all add: le_fun_def)
+instance by standard (simp_all add: le_fun_def)
 
 end
 
 instantiation "fun" :: (type, semilattice_inf) semilattice_inf
 begin
 
-definition
-  "f \<sqinter> g = (\<lambda>x. f x \<sqinter> g x)"
-
-lemma inf_apply [simp, code]:
-  "(f \<sqinter> g) x = f x \<sqinter> g x"
+definition "f \<sqinter> g = (\<lambda>x. f x \<sqinter> g x)"
+
+lemma inf_apply [simp, code]: "(f \<sqinter> g) x = f x \<sqinter> g x"
   by (simp add: inf_fun_def)
 
-instance proof
-qed (simp_all add: le_fun_def)
+instance by standard (simp_all add: le_fun_def)
 
 end
 
 instance "fun" :: (type, lattice) lattice ..
 
-instance "fun" :: (type, distrib_lattice) distrib_lattice proof
-qed (rule ext, simp add: sup_inf_distrib1)
+instance "fun" :: (type, distrib_lattice) distrib_lattice
+  by standard (rule ext, simp add: sup_inf_distrib1)
 
 instance "fun" :: (type, bounded_lattice) bounded_lattice ..
 
 instantiation "fun" :: (type, uminus) uminus
 begin
 
-definition
-  fun_Compl_def: "- A = (\<lambda>x. - A x)"
-
-lemma uminus_apply [simp, code]:
-  "(- A) x = - (A x)"
+definition fun_Compl_def: "- A = (\<lambda>x. - A x)"
+
+lemma uminus_apply [simp, code]: "(- A) x = - (A x)"
   by (simp add: fun_Compl_def)
 
 instance ..
 
 end
 
 instantiation "fun" :: (type, minus) minus
 begin
 
-definition
-  fun_diff_def: "A - B = (\<lambda>x. A x - B x)"
-
-lemma minus_apply [simp, code]:
-  "(A - B) x = A x - B x"
+definition fun_diff_def: "A - B = (\<lambda>x. A x - B x)"
+
+lemma minus_apply [simp, code]: "(A - B) x = A x - B x"
   by (simp add: fun_diff_def)
 
 instance ..
 
 end
 
-instance "fun" :: (type, boolean_algebra) boolean_algebra proof
-qed (rule ext, simp_all add: inf_compl_bot sup_compl_top diff_eq)+
+instance "fun" :: (type, boolean_algebra) boolean_algebra
+  by standard (rule ext, simp_all add: inf_compl_bot sup_compl_top diff_eq)+
 
 
 subsection \<open>Lattice on unary and binary predicates\<close>
 
 lemma inf1I: "A x \<Longrightarrow> B x \<Longrightarrow> (A \<sqinter> B) x"

   by (simp add: sup_fun_def) iprover
 
 lemma sup2E: "(A \<squnion> B) x y \<Longrightarrow> (A x y \<Longrightarrow> P) \<Longrightarrow> (B x y \<Longrightarrow> P) \<Longrightarrow> P"
   by (simp add: sup_fun_def) iprover
 
-text \<open>
-  \medskip Classical introduction rule: no commitment to \<open>A\<close> vs
-  \<open>B\<close>.
-\<close>
+text \<open> \<^medskip> Classical introduction rule: no commitment to \<open>A\<close> vs \<open>B\<close>.\<close>
 
 lemma sup1CI: "(\<not> B x \<Longrightarrow> A x) \<Longrightarrow> (A \<squnion> B) x"
   by (auto simp add: sup_fun_def)
 
 lemma sup2CI: "(\<not> B x y \<Longrightarrow> A x y) \<Longrightarrow> (A \<squnion> B) x y"

 no_notation
   less_eq (infix "\<sqsubseteq>" 50) and
   less (infix "\<sqsubset>" 50)
 
 end
-