## Codimension 4 Gorenstein

This website accompanies my paper

Gorenstein in codimension 4 - the general structure theory, 30 pp.

Algebraic Geometry in East Asia (Taipei Nov 2011), Advanced Studies in

Pure Mathematics 65 (2015) pp. 201-227, preprint arXiv:1304.5248, 30 pp.
Slides for MSRI lecture Apr 2013.

### Magma scripts:

Magma code for Section 2.3, Example 3.

baby Magma code for calculation of 3.2.

Nonsingularity calculations for ZZ/3 Godeaux surfaces and

related varieties.

Magma code for Fun2 and MSRI lecture

### Related papers and preprints:

David A. Buchsbaum and David Eisenbud,
What makes a complex exact?

J. Algebra. **25** (1973) 259-268

David A. Buchsbaum and David Eisenbud,
Algebra structures for finite

free
resolutions, and some structure theorems for ideals of codimension 3,

American J Math **99** (1977) 447-485

Miles Reid,
Parallel unprojection equations for ZZ/3 Godeaux surfaces

Notes, 9 pp.

Miles Reid,
Fun in codimension 4, notes, 24 pp.

Duncan Dicks, Surfaces with p_g=3, K^2=4 and extension-deformation

theory, 1988, Warwick
PhD thesis, 125 + vi pp.

Miles Reid,
Surfaces with p_g=3, K^2=4 according to E. Horikawa

and Duncan Dicks, Proceedings of Algebraic geometry mini-symposium

(Tokyo Univ., Dec 1989), 1--22

Miles Reid,
Graded rings and birational geometry, in Proc. of algebraic

geometry symposium (Kinosaki, Oct 2000), K. Ohno (Ed.), 1--72

Fabrizio Catanese, Wenfei Liu, Roberto Pignatelli, The moduli

space of even surfaces of general type with K^2=8, p_g=4 and q=0,

arXiv:1209.0034, 29 pp.

Gavin Brown, Michael Kerber and Miles Reid, Fano 3-folds in
codimension 4,

Tom and Jerry, Part I, Compositio **148** (May 2012) 1171--1194,

preprint arXiv:1009.4313, 33 pp.

See also notes in progress Tutorial on T and J

Stavros Papadakis and Miles Reid, Kustin--Miller unprojection without
complexes,

J. Alg. Geom. **13** (2004) 563--577, preprint
arXiv:0011094, 18 pp.

### Links:

Gavin Brown's graded ring database

The Magma online calculator.

Miles Reid's front page