Module Type NZLog2Spec (A : NZOrdAxiomsSig')(B : Pow' A)(C : Log2 A).

Axiom log2_spec : forall a, 0<a -> 2^(log2 a) <= a < 2^(S (log2 a)).
Axiom log2_nonpos : forall a, a<=0 -> log2 a == 0.