{ "id": "2007.11229", "version": "v1", "published": "2020-07-22T06:44:38.000Z", "updated": "2020-07-22T06:44:38.000Z", "title": "Classification of Fano 4-folds with Lefschetz defect 3 and Picard number 5", "authors": [ "Cinzia Casagrande", "Eleonora A. Romano" ], "comment": "16 pages", "categories": [ "math.AG" ], "abstract": "Let X be a smooth, complex Fano 4-fold, and rho(X) its Picard number. If X contains a prime divisor D with rho(X)-rho(D)>2, then either X is a product of del Pezzo surfaces, or rho(X)=5 or 6. In this setting, we completely classify the case where rho(X)=5; there are 6 families, among which one is new. We also deduce the classification of Fano 4-folds with rho(X)>4 with an elementary divisorial contraction sending a divisor to a curve.", "revisions": [ { "version": "v1", "updated": "2020-07-22T06:44:38.000Z" } ], "analyses": { "keywords": [ "picard number", "lefschetz defect", "classification", "del pezzo surfaces", "complex fano" ], "note": { "typesetting": "TeX", "pages": 16, "language": "en", "license": "arXiv", "status": "editable" } } }