src/HOL/Nat.thy
changeset 30056 0a35bee25c20
parent 29879 4425849f5db7
child 30079 293b896b9c25
equal deleted inserted replaced
30053:044308b4948a 30056:0a35bee25c20
   733   show "0 < (1::nat)" by simp
   733   show "0 < (1::nat)" by simp
   734   show "i \<le> j ==> k + i \<le> k + j" by simp
   734   show "i \<le> j ==> k + i \<le> k + j" by simp
   735   show "i < j ==> 0 < k ==> k * i < k * j" by (simp add: mult_less_mono2)
   735   show "i < j ==> 0 < k ==> k * i < k * j" by (simp add: mult_less_mono2)
   736 qed
   736 qed
   737 
   737 
       
   738 instance nat :: no_zero_divisors
       
   739 proof
       
   740   fix a::nat and b::nat show "a ~= 0 \<Longrightarrow> b ~= 0 \<Longrightarrow> a * b ~= 0" by auto
       
   741 qed
       
   742 
   738 lemma nat_mult_1: "(1::nat) * n = n"
   743 lemma nat_mult_1: "(1::nat) * n = n"
   739 by simp
   744 by simp
   740 
   745 
   741 lemma nat_mult_1_right: "n * (1::nat) = n"
   746 lemma nat_mult_1_right: "n * (1::nat) = n"
   742 by simp
   747 by simp