Comment on: Detecting Vanishing Dimensions Via Primordial Gravitational   Wave Astronomy
  It has been recently claimed [arXiv:1102.3434] that quantum gravity models where the number of dimensions reduces at the ultraviolet exhibit a potentially observable cutoff in the primordial gravitational wave spectrum, and that this is a "generic" and "robust" test for such models, since "(2+1)-dimensional spacetimes have no gravitational degrees of freedom". We argue that such a claim is misleading. 
Thomas P. Sotiriou, Matt Visser, Silke Weinfurtner
gr-qc hep-th