Remarks on a conjecture of Huneke and Wiegand and the vanishing of (co)homology

TL;DR

This paper investigates a longstanding conjecture related to torsion in tensor products over local domains, using Hochster's theta invariant and exploring conditions under which the conjecture holds.

Contribution

It proves the conjecture for two periodic modules and introduces a new condition involving hypersurface rings that implies the conjecture for complete intersections.

Findings

The conjecture holds for two periodic modules.

A new condition over hypersurface rings is formulated.

Interactions between Tate (co)homology vanishing and torsion are explored.

Abstract

In this paper we study a long-standing conjecture of Huneke and Wiegand which is concerned with the torsion submodule of certain tensor products of modules over one-dimensional local domains. We utilize Hochster's theta invariant and show that the conjecture is true for two periodic modules. We also make use of a result of Orlov and formulate a new condition which, if true over hypersurface rings, forces the conjecture of Huneke and Wiegand to be true over complete intersection rings of arbitrary codimension. Along the way we investigate the interaction between the vanishing of Tate (co)homology and torsion in tensor products of modules, and obtain new results that are of independent interest.