{ "id": "1110.5580", "version": "v3", "published": "2011-10-24T13:41:10.000Z", "updated": "2011-11-28T15:49:12.000Z", "title": "Codimension Two Determinantal Varieties with Isolated Singularities", "authors": [ "Miriam da Silva Pereira", "Maria Aparecida Soares Ruas" ], "categories": [ "math.AG" ], "abstract": "We study codimension two determinantal varieties with isolated singularities. These singularities admit a unique smoothing, thus we can define their Milnor number as the middle Betti number of their generic fiber. For surfaces in C^4, we obtain a L\\^e-Greuel formula expressing the Milnor number of the surface in terms of the second polar multiplicity and the Milnor number of a generic section. We also relate the Milnor number with Ebeling and Gusein-Zade index of the 1- form given by the differential of a generic linear projection defined on the surface. To illustrate the results, in the last section we compute the Milnor number of some normal forms from A. Fr\\\"uhbis-Kr\\\"uger and A. Neumer [2] list of simple determinantal surface singularities.", "revisions": [ { "version": "v3", "updated": "2011-11-28T15:49:12.000Z" } ], "analyses": { "keywords": [ "milnor number", "determinantal varieties", "isolated singularities", "simple determinantal surface singularities", "generic linear projection" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2011arXiv1110.5580D" } } }