Equivalence of diagonal contractions to generalized IW-contractions with integer exponents

We present a simple and rigorous proof of the claim by Weimar-Woods [Rev. Math. Phys. 12 (2000) 1505-1529] that any diagonal contraction (e.g., a generalized In"on"u-Wigner contraction) is equivalent to a generalized In"on"u-Wigner contraction with integer parameter powers.