3 papers
math.AC2026
Cosyzygy modules
Petter Andreas Bergh, David A. Jorgensen, Peder Thompson
We characterize all first cosyzygy modules of a given finitely generated module over a local ring. We do this by introducing the notion of a canonical cosyzygy module, and showing…
math.RA2026
Acyclic complexes and regular rings
Lars Winther Christensen, Sergio Estrada, Peder Thompson
A 2009 paper by Iacob and Iyengar characterizes noetherian regular rings in terms of properties of complexes of projective modules, flat modules, and injective modules. We show tha…
math.AC2025
Dimension and depth inequalities over complete intersections
Petter Andreas Bergh, David A. Jorgensen, Peder Thompson
For a pair of finitely generated modules and over a codimension complete intersection ring with finite, we pay special attention to the inequali…