src/HOL/Algebra/Multiplicative_Group.thy
changeset 69785 9e326f6f8a24
parent 69749 10e48c47a549
child 69895 6b03a8cf092d
equal deleted inserted replaced
69784:24bbc4e30e5b 69785:9e326f6f8a24
   134  fixes n p :: nat
   134  fixes n p :: nat
   135  assumes "p > 0" "n dvd p"
   135  assumes "p > 0" "n dvd p"
   136  shows "n > 0 \<and> n \<le> p"
   136  shows "n > 0 \<and> n \<le> p"
   137  using assms by (simp add: dvd_pos_nat dvd_imp_le)
   137  using assms by (simp add: dvd_pos_nat dvd_imp_le)
   138 
   138 
   139 (* Deviates from the definition given in the library in number theory *)
   139 (* TODO FIXME: This is the "totient" function from HOL-Number_Theory, but since part of
       
   140    HOL-Number_Theory depends on HOL-Algebra.Multiplicative_Group, there would be a cyclic
       
   141    dependency. *)
   140 definition phi' :: "nat => nat"
   142 definition phi' :: "nat => nat"
   141   where "phi' m = card {x. 1 \<le> x \<and> x \<le> m \<and> coprime x m}"
   143   where "phi' m = card {x. 1 \<le> x \<and> x \<le> m \<and> coprime x m}"
   142 
   144 
   143 notation (latex output)
   145 notation (latex output)
   144   phi' ("\<phi> _")
   146   phi' ("\<phi> _")