English

Independence of the total reflexivity conditions for modules

Commutative Algebra 2007-05-23 v2

Abstract

We show that the conditions defining total reflexivity for modules are independent. In particular, we construct a commutative Noetherian local ring RR and a reflexive RR-module MM such that \ExtRi(M,R)=0\Ext^i_R(M,R)=0 for all i>0i>0, but \ExtRi(M,R)0\Ext^i_R(M^*,R)\ne 0 for all i>0i>0.

Keywords

Cite

@article{arxiv.math/0410257,
  title  = {Independence of the total reflexivity conditions for modules},
  author = {David Jorgensen and Liana Sega},
  journal= {arXiv preprint arXiv:math/0410257},
  year   = {2007}
}

Comments

In the previous version, Proposition 2.1 is incorrect, as stated. We added the assumption "Artinian" in the statement

R2 v1 2026-07-22T17:11:02.231Z