Bounds on the Castelnuovo-mumford Regularity of Tensor Products
نویسنده
چکیده
In this paper we show how, given a complex of graded modules and knowing some partial Castelnuovo-Mumford regularities for all the modules in the complex and for all the positive homologies, it is possible to get a bound on the regularity of the zero homology. We use this to prove that if dimTor 1 (M, N) ≤ 1 then reg(M⊗N) ≤ reg(M)+reg(N), generalizing results of Chandler, Conca and Herzog, and Sidman. Finally we give a description of the regularity of a module in terms of the postulation numbers of filter regular hyperplane restrictions.
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