On the computation of a-invariants

Research paper by Winfried Bruns, Jürgen Herzog

Indexed on: 01 Dec '92Published on: 01 Dec '92Published in: Manuscripta Mathematica

Abstract

Thea-invariant of a graded Cohen-Macaulay ring is the least degree of a generator of its graded canonical module. We compute thea-invariants of (i) graded algebras with straightening laws on upper semi-modular lattices and (ii) the Stanley-Reisner rings of shellable weighted simplicial complexes. The formulas obtained are applied to rings defined by determinantal and pfaffian ideals.