Gluing semigroups and strongly indispensable free resolutions

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ŞAHİN M., Stella L. G.

INTERNATIONAL JOURNAL OF ALGEBRA AND COMPUTATION, vol.29, no.2, pp.263-278, 2019 (SCI-Expanded) identifier identifier


We study strong indispensability of minimal free resolutions of semigroup rings focusing on the operation of gluing used in the literature to take examples with a special property and produce new ones. We give a naive condition to determine whether gluing of two semigroup rings has a strongly indispensable minimal free resolution. As applications, we determine simple gluings of 3-generated non-symmetric, 4-generated symmetric and pseudo symmetric numerical semigroups as well as obtain infinitely many new complete intersection semigroups of any embedding dimensions, having strongly indispensable minimal free resolutions.