When are syzygies of the residue field self-dual?

Abstract

Finitely generated reflexive modules over commutative Noetherian rings form a key component of Auslander and Bridger's stable module theory and are likewise essential in the study of Cohen--Macaulay representations. Recently, H. Dao characterized Arf local rings as exactly those one-dimensional Cohen--Macaulay local rings over which every finitely generated reflexive module is self-dual, and raised the general question of characterizing rings over which every finitely generated reflexive module is self-dual. Motivated by this, in this article, we study the question of self-duality of syzygies of the residue field of a local ring when they are known to be reflexive. We show that for local rings of depth at least 2, the answer is given by hypersurface or regular local rings in most cases.