Newton-Okounkov bodies and Picard numbers on surfaces
We study the shapes of all Newton-Okounkov bodies ∆v(D) of a given big divisor D on a surface S with respect to all rank 2 valuations v of K(S). We obtain upper bounds for, and in many cases we determine exactly, the possible numbers of vertices of the bodies ∆v(D). The upper bounds are expressed in...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universitat Autònoma de Barcelona |
| Repositorio: | Dipòsit Digital de Documents de la UAB |
| Idioma: | inglés |
| OAI Identifier: | oai:ddd.uab.cat:304450 |
| Acceso en línea: | https://ddd.uab.cat/record/304450 https://dx.doi.org/urn:doi:10.5565/PUBLMAT6912501 |
| Access Level: | acceso abierto |
| Palabra clave: | Valuation Blowup Newton-Okounkov body Algebraic surface Picard number |
| Sumario: | We study the shapes of all Newton-Okounkov bodies ∆v(D) of a given big divisor D on a surface S with respect to all rank 2 valuations v of K(S). We obtain upper bounds for, and in many cases we determine exactly, the possible numbers of vertices of the bodies ∆v(D). The upper bounds are expressed in terms of Picard numbers and they are birationally invariant, as they do not depend on the model S˜ where the valuation v becomes a flag valuation. We also conjecture that the set of all Newton-Okounkov bodies of a single ample divisor D determines the Picard number of S, and prove that this is the case for Picard number 1, by an explicit characterization of surfaces of Picard number 1 in terms of Newton-Okounkov bodies. |
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