Journal of Algebraic Geometry

Author(s): Stavros Argyrios Papadakis
Journal: J. Algebraic Geom. 13 (2004), 249-268.
Posted: October 15, 2003
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Abstract: A main ingredient for the Kustin-Miller unprojection is the module $\operatorname{Hom}_R(I, \omega_R)$ , where

is a local Gorenstein ring and

a codimension one ideal with

Gorenstein. We prove a method of calculating it in a relative setting using resolutions. We give three applications. In the first we generalise a result of Catanese, Franciosi, Hulek, and Reid (Embeddings of curves and surfaces, Nagoya Math. J. 154 (1999), 185-220). The second and the third are about Tom and Jerry, two families of Gorenstein codimension four rings with $9 \times 16$ resolutions.

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Stavros Argyrios Papadakis
Affiliation: Math Institute, University of Warwick, Coventry CV4 7AL, England
Address at time of publication: Fakultät für Mathematik und Informatik, Geb. 27, Universität des Saarlandes, D-66123 Saarbrücken, Gernamy
Email: spapad@maths.warwick.ac.uk, papadakis@math.uni-sb.de

PII: S 1056-3911(03)00350-3
Received by editor(s): August 24, 2001
Posted: October 15, 2003
Additional Notes: This work is part of a Warwick Ph.D. thesis \cite{P}, financially supported by the Greek State Scholarships Foundation

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