Institute of Mathematics and Informatics at the Bulgarian Academy of Sciences
Pliska Studia Mathematica Bulgarica, Vol. 2, No 1, (1981), 167p-172p
A change of rings theorem is proved for the reduction of the Poincaré series of a local Gorenstein ring modulo depth 3 perfect ideals, minimally generated by 4 elements. Together with an earlier result of the author, this theorem establishes the rationality of the Poincaré series of the title.