src/HOL/Power.thy
changeset 23305 8ae6f7b0903b
parent 23183 af27d3ad9baf
child 23431 25ca91279a9b
equal deleted inserted replaced
23304:83f3b6dc58b5 23305:8ae6f7b0903b
   328 proof
   328 proof
   329   fix z n :: nat
   329   fix z n :: nat
   330   show "z^0 = 1" by simp
   330   show "z^0 = 1" by simp
   331   show "z^(Suc n) = z * (z^n)" by simp
   331   show "z^(Suc n) = z * (z^n)" by simp
   332 qed
   332 qed
       
   333 
       
   334 lemma of_nat_power:
       
   335   "of_nat (m ^ n) = (of_nat m::'a::{semiring_1,recpower}) ^ n"
       
   336 by (induct n, simp_all add: power_Suc)
   333 
   337 
   334 lemma nat_one_le_power [simp]: "1 \<le> i ==> Suc 0 \<le> i^n"
   338 lemma nat_one_le_power [simp]: "1 \<le> i ==> Suc 0 \<le> i^n"
   335 by (insert one_le_power [of i n], simp)
   339 by (insert one_le_power [of i n], simp)
   336 
   340 
   337 lemma nat_zero_less_power_iff [simp]: "(0 < x^n) = (x \<noteq> (0::nat) | n=0)"
   341 lemma nat_zero_less_power_iff [simp]: "(0 < x^n) = (x \<noteq> (0::nat) | n=0)"