(m n : binnat) : unary m * unary n = unary (m * n). Proof. etransitivity (unary (binary (_^-1 m * _^-1 n))). - apply ((eissect binary (unary m * unary n)) ^). - rewrite <- binarymult. rewrite (eisretr binary m), (eisretr binary n). reflexivity. Qed.
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