Created
December 23, 2014 05:45
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theory Exponents | |
imports Main | |
begin | |
lemma rMulComm: "(a*b ::int) = (b*a ::int)" | |
by (rule Groups.ab_semigroup_mult_class.mult.commute) | |
lemma rExpMul: "((a^b)^c ::int) = (a^(b*c) ::int)" | |
by (rule Int.zpower_zpower) | |
theorem "((a^b)^c ::int) = ((a^c)^b :: int)" | |
(* 0. (a^b)^c | |
1. a^(b*c) by rExpMul | |
2. a^(c*b) by rMulComm | |
3. (a^c)^b by rExpMul | |
*) | |
end |
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