src/HOL/Analysis/Vitali_Covering_Theorem.thy

               by (simp add: case_prod_app prod.case_distrib sum_distrib_left)
             also have "\<dots> = e * (?\<mu> (\<Union>(x,r)\<in>I. ball x r) / ?\<mu> (ball z 1))"
               apply (subst measure_UNION')
               using that pwC by (auto simp: case_prod_unfold elim: pairwise_mono)
             also have "\<dots> \<le> e"
-              by (metis mult.commute mult.left_neutral mult_le_cancel_iff1 \<open>e > 0\<close> le1)
+              by (metis mult.commute mult.left_neutral mult_le_cancel_right_pos \<open>e > 0\<close> le1)
             finally show ?thesis .
           qed
           have "\<Union>(U ` C) \<in> lmeasurable" "?\<mu> (\<Union>(U ` C)) \<le> e"
             using \<open>e > 0\<close> Um lee
             by(auto intro!: fmeasurable_UN_bound [OF \<open>countable C\<close>] measure_UN_bound [OF \<open>countable C\<close>])