English

Cohen-Macaulayness and canonical module of residual intersections

Commutative Algebra 2019-07-30 v4 Algebraic Geometry

Abstract

We show the Cohen-Macaulayness and describe the canonical module of residual intersections J=a ⁣:RIJ=\mathfrak{a}\colon_R I in a Cohen-Macaulay local ring RR, under sliding depth type hypotheses. For this purpose, we construct and study, using a recent article of Hassanzadeh and the second named author, a family of complexes that contains important informations on a residual intersection and its canonical module. We also determine several invariants of residual intersections as the graded canonical module, the Hilbert series, the Castelnuovo-Mumford regularity and the type. Finally, whenever II is strongly Cohen-Macaulay, we show duality results for residual intersections that are closely connected to results by Eisenbud and Ulrich. It establishes some tight relations between the Hilbert series of some symmetric powers of I/aI/\mathfrak{a}. We also provide closed formulas for the types and for the Bass numbers of some symmetric powers of I/a.I/\mathfrak{a}.

Keywords

Cite

@article{arxiv.1701.08087,
  title  = {Cohen-Macaulayness and canonical module of residual intersections},
  author = {Marc Chardin and José Naéliton and Quang Hoa Tran},
  journal= {arXiv preprint arXiv:1701.08087},
  year   = {2019}
}

Comments

28 pages. Comments are welcome

R2 v1 2026-06-22T18:02:32.458Z