src/HOL/Algebra/Divisibility.thy
changeset 67343 f0f13aa282f4
parent 66579 2db3fe23fdaf
child 67399 eab6ce8368fa
equal deleted inserted replaced
67342:7905adb28bdc 67343:f0f13aa282f4
   143   where "a divides\<^bsub>G\<^esub> b \<longleftrightarrow> (\<exists>c\<in>carrier G. b = a \<otimes>\<^bsub>G\<^esub> c)"
   143   where "a divides\<^bsub>G\<^esub> b \<longleftrightarrow> (\<exists>c\<in>carrier G. b = a \<otimes>\<^bsub>G\<^esub> c)"
   144 
   144 
   145 definition associated :: "[_, 'a, 'a] \<Rightarrow> bool" (infix "\<sim>\<index>" 55)
   145 definition associated :: "[_, 'a, 'a] \<Rightarrow> bool" (infix "\<sim>\<index>" 55)
   146   where "a \<sim>\<^bsub>G\<^esub> b \<longleftrightarrow> a divides\<^bsub>G\<^esub> b \<and> b divides\<^bsub>G\<^esub> a"
   146   where "a \<sim>\<^bsub>G\<^esub> b \<longleftrightarrow> a divides\<^bsub>G\<^esub> b \<and> b divides\<^bsub>G\<^esub> a"
   147 
   147 
   148 abbreviation "division_rel G \<equiv> \<lparr>carrier = carrier G, eq = op \<sim>\<^bsub>G\<^esub>, le = op divides\<^bsub>G\<^esub>\<rparr>"
   148 abbreviation "division_rel G \<equiv> \<lparr>carrier = carrier G, eq = op \<sim>\<^bsub>G\<^esub>, le = (op divides\<^bsub>G\<^esub>)\<rparr>"
   149 
   149 
   150 definition properfactor :: "[_, 'a, 'a] \<Rightarrow> bool"
   150 definition properfactor :: "[_, 'a, 'a] \<Rightarrow> bool"
   151   where "properfactor G a b \<longleftrightarrow> a divides\<^bsub>G\<^esub> b \<and> \<not>(b divides\<^bsub>G\<^esub> a)"
   151   where "properfactor G a b \<longleftrightarrow> a divides\<^bsub>G\<^esub> b \<and> \<not>(b divides\<^bsub>G\<^esub> a)"
   152 
   152 
   153 definition irreducible :: "[_, 'a] \<Rightarrow> bool"
   153 definition irreducible :: "[_, 'a] \<Rightarrow> bool"