src/HOL/Hahn_Banach/Function_Norm.thy
changeset 44887 7ca82df6e951
parent 36778 739a9379e29b
child 46867 0883804b67bb
equal deleted inserted replaced
44886:6ca299d29bdd 44887:7ca82df6e951
   141           also have "\<dots> = c * (\<parallel>x\<parallel> * inverse \<parallel>x\<parallel>)"
   141           also have "\<dots> = c * (\<parallel>x\<parallel> * inverse \<parallel>x\<parallel>)"
   142             by (rule Groups.mult_assoc)
   142             by (rule Groups.mult_assoc)
   143           also
   143           also
   144           from gt have "\<parallel>x\<parallel> \<noteq> 0" by simp
   144           from gt have "\<parallel>x\<parallel> \<noteq> 0" by simp
   145           then have "\<parallel>x\<parallel> * inverse \<parallel>x\<parallel> = 1" by simp 
   145           then have "\<parallel>x\<parallel> * inverse \<parallel>x\<parallel> = 1" by simp 
   146           also have "c * 1 \<le> b" by (simp add: b_def le_maxI1)
   146           also have "c * 1 \<le> b" by (simp add: b_def)
   147           finally show "y \<le> b" .
   147           finally show "y \<le> b" .
   148         qed
   148         qed
   149       qed
   149       qed
   150       then show ?thesis ..
   150       then show ?thesis ..
   151     qed
   151     qed