diff -r d2e5df3d1201 -r 65f8680c3f16 src/HOL/Algebra/Bij.thy --- a/src/HOL/Algebra/Bij.thy Fri Apr 23 20:52:04 2004 +0200 +++ b/src/HOL/Algebra/Bij.thy Fri Apr 23 21:46:04 2004 +0200 @@ -3,41 +3,41 @@ Author: Florian Kammueller, with new proofs by L C Paulson *) - -header{*Bijections of a Set, Permutation Groups, Automorphism Groups*} +header {* Bijections of a Set, Permutation Groups, Automorphism Groups *} theory Bij = Group: constdefs - Bij :: "'a set => (('a => 'a)set)" + Bij :: "'a set => ('a => 'a) set" --{*Only extensional functions, since otherwise we get too many.*} - "Bij S == extensional S \ {f. f`S = S & inj_on f S}" + "Bij S == extensional S \ {f. f`S = S & inj_on f S}" - BijGroup :: "'a set => (('a => 'a) monoid)" - "BijGroup S == (| carrier = Bij S, - mult = %g: Bij S. %f: Bij S. compose S g f, - one = %x: S. x |)" + BijGroup :: "'a set => ('a => 'a) monoid" + "BijGroup S == + (| carrier = Bij S, + mult = %g: Bij S. %f: Bij S. compose S g f, + one = %x: S. x |)" declare Id_compose [simp] compose_Id [simp] lemma Bij_imp_extensional: "f \ Bij S ==> f \ extensional S" -by (simp add: Bij_def) + by (simp add: Bij_def) lemma Bij_imp_funcset: "f \ Bij S ==> f \ S -> S" -by (auto simp add: Bij_def Pi_def) + by (auto simp add: Bij_def Pi_def) lemma Bij_imp_apply: "f \ Bij S ==> f ` S = S" -by (simp add: Bij_def) + by (simp add: Bij_def) lemma Bij_imp_inj_on: "f \ Bij S ==> inj_on f S" -by (simp add: Bij_def) + by (simp add: Bij_def) lemma BijI: "[| f \ extensional(S); f`S = S; inj_on f S |] ==> f \ Bij S" -by (simp add: Bij_def) + by (simp add: Bij_def) -subsection{*Bijections Form a Group*} +subsection {*Bijections Form a Group *} lemma restrict_Inv_Bij: "f \ Bij S ==> (%x:S. (Inv S f) x) \ Bij S" apply (simp add: Bij_def) @@ -60,7 +60,7 @@ lemma compose_Bij: "[| x \ Bij S; y \ Bij S|] ==> compose S x y \ Bij S" apply (rule BijI) - apply (simp add: compose_extensional) + apply (simp add: compose_extensional) apply (blast del: equalityI intro: surj_compose dest: Bij_imp_apply Bij_imp_inj_on) apply (blast intro: inj_on_compose dest: Bij_imp_apply Bij_imp_inj_on) @@ -70,44 +70,44 @@ "f \ Bij S ==> compose S (restrict (Inv S f) S) f = (\x\S. x)" apply (rule compose_Inv_id) apply (simp add: Bij_imp_inj_on) -apply (simp add: Bij_imp_apply) +apply (simp add: Bij_imp_apply) done theorem group_BijGroup: "group (BijGroup S)" -apply (simp add: BijGroup_def) +apply (simp add: BijGroup_def) apply (rule groupI) apply (simp add: compose_Bij) apply (simp add: id_Bij) apply (simp add: compose_Bij) apply (blast intro: compose_assoc [symmetric] Bij_imp_funcset) apply (simp add: id_Bij Bij_imp_funcset Bij_imp_extensional, simp) -apply (blast intro: Bij_compose_restrict_eq restrict_Inv_Bij) +apply (blast intro: Bij_compose_restrict_eq restrict_Inv_Bij) done subsection{*Automorphisms Form a Group*} lemma Bij_Inv_mem: "[| f \ Bij S; x : S |] ==> Inv S f x : S" -by (simp add: Bij_def Inv_mem) +by (simp add: Bij_def Inv_mem) lemma Bij_Inv_lemma: assumes eq: "!!x y. [|x \ S; y \ S|] ==> h(g x y) = g (h x) (h y)" - shows "[| h \ Bij S; g \ S \ S \ S; x \ S; y \ S |] + shows "[| h \ Bij S; g \ S \ S \ S; x \ S; y \ S |] ==> Inv S h (g x y) = g (Inv S h x) (Inv S h y)" -apply (simp add: Bij_def) +apply (simp add: Bij_def) apply (subgoal_tac "EX x':S. EX y':S. x = h x' & y = h y'", clarify) apply (simp add: eq [symmetric] Inv_f_f funcset_mem [THEN funcset_mem], blast) done constdefs - auto :: "('a,'b) monoid_scheme => ('a => 'a)set" + auto :: "('a, 'b) monoid_scheme => ('a => 'a) set" "auto G == hom G G \ Bij (carrier G)" - AutoGroup :: "[('a,'c) monoid_scheme] => ('a=>'a) monoid" + AutoGroup :: "('a, 'c) monoid_scheme => ('a => 'a) monoid" "AutoGroup G == BijGroup (carrier G) (|carrier := auto G |)" lemma id_in_auto: "group G ==> (%x: carrier G. x) \ auto G" - by (simp add: auto_def hom_def restrictI group.axioms id_Bij) + by (simp add: auto_def hom_def restrictI group.axioms id_Bij) lemma mult_funcset: "group G ==> mult G \ carrier G -> carrier G -> carrier G" by (simp add: Pi_I group.axioms) @@ -122,27 +122,26 @@ "f \ Bij S ==> m_inv (BijGroup S) f = (%x: S. (Inv S f) x)" apply (rule group.inv_equality) apply (rule group_BijGroup) -apply (simp_all add: BijGroup_def restrict_Inv_Bij Bij_compose_restrict_eq) +apply (simp_all add: BijGroup_def restrict_Inv_Bij Bij_compose_restrict_eq) done lemma subgroup_auto: "group G ==> subgroup (auto G) (BijGroup (carrier G))" -apply (rule group.subgroupI) - apply (rule group_BijGroup) - apply (force simp add: auto_def BijGroup_def) - apply (blast intro: dest: id_in_auto) +apply (rule group.subgroupI) + apply (rule group_BijGroup) + apply (force simp add: auto_def BijGroup_def) + apply (blast intro: dest: id_in_auto) apply (simp del: restrict_apply - add: inv_BijGroup auto_def restrict_Inv_Bij restrict_Inv_hom) + add: inv_BijGroup auto_def restrict_Inv_Bij restrict_Inv_hom) apply (simp add: BijGroup_def auto_def Bij_imp_funcset compose_hom compose_Bij) done theorem AutoGroup: "group G ==> group (AutoGroup G)" -apply (simp add: AutoGroup_def) +apply (simp add: AutoGroup_def) apply (rule Group.subgroup.groupI) -apply (erule subgroup_auto) -apply (insert Bij.group_BijGroup [of "carrier G"]) -apply (simp_all add: group_def) +apply (erule subgroup_auto) +apply (insert Bij.group_BijGroup [of "carrier G"]) +apply (simp_all add: group_def) done end -