src/HOL/Finite_Set.thy
changeset 15281 bd4611956c7b
parent 15234 ec91a90c604e
child 15308 56c830f91b38
equal deleted inserted replaced
15280:e0e9bf44afad 15281:bd4611956c7b
   120 
   120 
   121 lemma finite_insert [simp]: "finite (insert a A) = finite A"
   121 lemma finite_insert [simp]: "finite (insert a A) = finite A"
   122   apply (subst insert_is_Un)
   122   apply (subst insert_is_Un)
   123   apply (simp only: finite_Un, blast)
   123   apply (simp only: finite_Un, blast)
   124   done
   124   done
       
   125 
       
   126 lemma finite_Union[simp, intro]:
       
   127  "\<lbrakk> finite A; !!M. M \<in> A \<Longrightarrow> finite M \<rbrakk> \<Longrightarrow> finite(\<Union>A)"
       
   128 by (induct rule:finite_induct) simp_all
   125 
   129 
   126 lemma finite_empty_induct:
   130 lemma finite_empty_induct:
   127   "finite A ==>
   131   "finite A ==>
   128   P A ==> (!!a A. finite A ==> a:A ==> P A ==> P (A - {a})) ==> P {}"
   132   P A ==> (!!a A. finite A ==> a:A ==> P A ==> P (A - {a})) ==> P {}"
   129 proof -
   133 proof -