IPM Calendar 
Sunday 29 November 2020   Today  
Events for day: Thursday 19 November 2020    
           11:00 - 13:00     Commutative Algebra Webinar
Almost Gorenstein Property for Affine Semigroup Rings


The almost Gorenstein property appeared in the work of Barucci and Fr�oberg in the context of 1-dimensional analytical unramified rings. It was extended to 1- dimensional local rings by Goto, Matsuoka and Thi Phuong, and later on to rings of higher dimension by Goto, Takahashi and Taniguchi. Let R be a positively graded Cohen-Macaulay K-algebra with canonical module ωR. We let a = − min{k ∈ Z : (ωR)k 6= 0}, which is also known as the a-invariant of R. R is called (graded) almost Gorenstein if there exists an exact sequence of graded R-modules 0 → R → ωR(−a) → E → 0, where ...