The main object of the present paper is a numerical criterion determining when a Weil divisor of a QQ –factorial complete toric variety admits a positive multiple Cartier divisor which is either numerically effective (nef) or ample. It is a consequence of ZZ –linear interpretation of Gale duality and secondary fan as developed in several previous papers of us. As a byproduct we get a computation of the Cartier index of a Weil divisor and a numerical characterization of weak QQ –Fano, QQ –Fano, Gorenstein, weak Fano and Fano toric varieties. Several examples are then given and studied.
A numerical ampleness criterion via Gale duality
ROSSI, Michele;TERRACINI, Lea
2017-01-01
Abstract
The main object of the present paper is a numerical criterion determining when a Weil divisor of a QQ –factorial complete toric variety admits a positive multiple Cartier divisor which is either numerically effective (nef) or ample. It is a consequence of ZZ –linear interpretation of Gale duality and secondary fan as developed in several previous papers of us. As a byproduct we get a computation of the Cartier index of a Weil divisor and a numerical characterization of weak QQ –Fano, QQ –Fano, Gorenstein, weak Fano and Fano toric varieties. Several examples are then given and studied.File in questo prodotto:
File | Dimensione | Formato | |
---|---|---|---|
1504.07014v3_4aperto.pdf
Accesso aperto
Descrizione: Articolo principale
Tipo di file:
POSTPRINT (VERSIONE FINALE DELL’AUTORE)
Dimensione
2.03 MB
Formato
Adobe PDF
|
2.03 MB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.