English

Asymmetric complete resolutions and vanishing of Ext over Gorenstein rings

Commutative Algebra 2007-05-23 v1

Abstract

We construct a class of Gorenstein local rings RR which admit minimal complete RR-free resolutions \bdC\bd C such that the sequence {\rankRCi}\{\rank_R C_i\} is constant for i<0i< 0, and grows exponentially for all i>0i>0. Over these rings we show that there exist finitely generated RR-modules MM and NN such that \ExtRi(M,N)=0\Ext^i_R(M,N)=0 for all i>0i> 0, but \ExtRi(N,M)0\Ext^i_R(N,M)\ne 0 for all i>0i>0.

Keywords

Cite

@article{arxiv.math/0510644,
  title  = {Asymmetric complete resolutions and vanishing of Ext over Gorenstein rings},
  author = {David A. Jorgensen and Liana M. Sega},
  journal= {arXiv preprint arXiv:math/0510644},
  year   = {2007}
}

Comments

14 pages, to appear in Internat. Math. Res. Notices