Upper bounds for the betti numbers of graded ideals of a given length in the exterior algebra
作者:
Marilena Crupi,
Rosanna Utano,
期刊:
Communications in Algebra
(Taylor Available online 1999)
卷期:
Volume 27,
issue 9
页码: 4607-4631
ISSN:0092-7872
年代: 1999
DOI:10.1080/00927879908826718
出版商: Gordon and Breach Science Publishers Ltd.
数据来源: Taylor
摘要:
LetEbe the exterior algebra of a finite dimensional vector space over a fieldK. Hilbert functions and Betti numbers of graded idealsi⊂Eare studied. It is shown that there exists a unique graded idealJ⊂Esuch that for all graded idealsI⊂Egenerated in degree ≥ 2 such thatone hasfor alli. Hereis thei-th Betti number of a gradedE-moduleM. The unique idealJwith the above property has “maximal” Hiibert function. Our result is the analogue of a theorem of Valla [10] which he proved for graded ideals in the polynomial ring. We further prove a similar inequality for the Bass numbers ofE/I, and give a combinatorial application.
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