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. 
Dmytro R. Popovych, Roman O. Popovych