Terracini Loci for Maps

Autor: Edoardo Ballico
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: AppliedMath, Vol 3, Iss 3, Pp 690-701 (2023)
Druh dokumentu: article
ISSN: 2673-9909
DOI: 10.3390/appliedmath3030036
Popis: Let X be a smooth projective variety and f:X→Pr a morphism birational onto its image. We define the Terracini loci of the map f. Most results are only for the case dimX=1. With this new and more flexible definition, it is possible to prove strong nonemptiness results with the full classification of all exceptional cases. We also consider Terracini loci with restricted support (solutions not intersecting a closed set B⊊X or solutions containing a prescribed p∈X). Our definitions work both for the Zariski and the euclidean topology and we suggest extensions to the case of real varieties. We also define Terracini loci for joins of two or more subvarieties of the same projective space. The proofs use algebro-geometric tools.
Databáze: Directory of Open Access Journals