3:45PM: Maximal CohenMacaulay (MCM) approximations over a Gorenstein local ringMengyuan ZhangThe theory of MCM approximations over a Gorenstein local ring was developed by M.Auslander and R.Buchweitz. The maximal rank of a free summand in the minimal approximating MCM module is an invariant of the original module, called the Auslander invariant. This was first studied by S.Ding in his thesis, where he gave a characterization of abstract hypersurfaces using the Auslander invariant. Over a hypersurface ring, A.Martsinkovsky demonstrated an intimate relation between the Auslander invariant and the CI operator. We will survey these results.

5:00PM: Commutative Algebra Learning SeminarChris Eurn/a
