Rees Algebras of Truncations of Complete Intersections
نویسنده
چکیده
In this paper we describe the defining equations of the Rees algebra and the special fiber ring of a truncation I of a complete intersection ideal in a polynomial ring over a field with homogeneous maximal ideal m. To describe explicitly the Rees algebra R(I) in terms of generators and relations we map another Rees ring R(M) onto it, where M is the direct sum of powers of m. We compute a Gröbner basis of the ideal definingR(M). It turns out that the normal domainR(M) is a Koszul algebra and from this we deduce that in many instancesR(I) is a Koszul algebra as well.
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