Structure theorems for some classes of grade four Gorenstein ideals
Bull. Korean Math. Soc. 2017 Vol. 54, No. 1, 99-124 https://doi.org/10.4134/BKMS.b150807 Published online December 21, 2016 Printed January 31, 2017
Yong Sung Cho, Oh-Jin Kang, and Hyoung June Ko Mokpo National University, Korea Aerospace University, Yonsei University
Abstract : The structure theorems \cite{3, 6, 21} for the classes of perfect ideals of grade 3 have been generalized to the structure theorems for the classes of perfect ideals linked to almost complete intersections of grade 3 by a regular sequence \cite{15}. In this paper we obtain structure theorems for two classes of Gorenstein ideals of grade 4 expressed as the sum of a perfect ideal of grade 3 (except a Gorenstein ideal of grade 3) and an almost complete intersection of grade 3 which are geometrically linked by a regular sequence.
Keywords : Gorenstein ideal of grade 4, linkage, minimal free resolution, perfect ideal of grade 3
