src/HOL/GCD.thy
changeset 66936 cf8d8fc23891
parent 66836 4eb431c3f974
child 67051 e7e54a0b9197
equal deleted inserted replaced
66935:d0f12783cd80 66936:cf8d8fc23891
  1598     by auto
  1598     by auto
  1599   ultimately show ?thesis
  1599   ultimately show ?thesis
  1600     by simp
  1600     by simp
  1601 next
  1601 next
  1602   case False
  1602   case False
  1603   then have "inj (times b)"
       
  1604     by (rule inj_times)
       
  1605   show ?thesis proof (cases "finite A")
  1603   show ?thesis proof (cases "finite A")
  1606     case False
  1604     case False
  1607     moreover from \<open>inj (times b)\<close>
  1605     moreover have "inj_on (times b) A"
  1608     have "inj_on (times b) A"
  1606       using \<open>b \<noteq> 0\<close> by (rule inj_on_mult)
  1609       by (rule inj_on_subset) simp
       
  1610     ultimately have "infinite (times b ` A)"
  1607     ultimately have "infinite (times b ` A)"
  1611       by (simp add: finite_image_iff)
  1608       by (simp add: finite_image_iff)
  1612     with False show ?thesis
  1609     with False show ?thesis
  1613       by simp
  1610       by simp
  1614   next
  1611   next