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One of the fundamental open questions in QFT is what kind of functions appear as Feynman integrals. In recent years this question has often been considered in a geometric context by interpreting the polynomials that appear in these…

High Energy Physics - Theory · Physics 2024-12-31 Rolf Schimmrigk

We completely classify the Q-factorial terminal toric Fano three-folds such that the sum of the squared torus invariant prime divisors is non-negative.

Algebraic Geometry · Mathematics 2023-02-22 Hiroshi Sato , Ryota Sumiyoshi

We prove results about 1-cycles on certain Fano varieties using techniques that rely on rational curves. Firstly, we show that Fano weighted complete intersections with index bigger than half their dimension have trivial first Griffiths…

Algebraic Geometry · Mathematics 2017-11-29 Cristian Minoccheri , Xuanyu Pan

Consider a Laurent polynomial with real positive coefficients such that the origin is strictly inside its Newton polytope. Then it is strongly convex as a function of real positive argument. So it has a distinguished Morse critical point…

Algebraic Geometry · Mathematics 2014-04-30 Sergey Galkin

In the presence of direct trajectories connecting source and drain contacts, the conductance of a quantum dot may exhibit resonances of the Fano type. Since Fano resonances result from the interference of two transmission pathways, their…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 A. A. Clerk , X. Waintal , P. W. Brouwer

Let $X\subset P^n$ be a complex projective manifold of degree $d$ and arbitrary dimension. The main result of this paper gives a classification of such manifolds (assumed moreover to be connected, non-degenerate and linearly normal) in case…

Algebraic Geometry · Mathematics 2007-05-23 Paltin Ionescu

We classify the terminal Fano threefolds of Picard number one that come with an effective action of a two-torus. Our approach applies also to higher dimensions and generalizes the correspondence between toric Fano varieties and lattice…

Algebraic Geometry · Mathematics 2025-07-08 Benjamin Bechtold , Elaine Huggenberger , Juergen Hausen , Michele Nicolussi

Let (M,E) be a generalized polarized manifold, i.e., a pair of an n-dimensional smooth projective variety and an ample vector bundle E of rank r on M. Let t be the nef value of a polarized manifold (M, det E), i.e., the minimum of the set…

Algebraic Geometry · Mathematics 2007-05-23 Masahiro Ohno

We show that if on a compact Kahler threefold there is a solution of the Kahler-Ricci flow which encounters a finite time collapsing singularity, then the manifold admits a Fano fibration. Furthermore, if there is finite time extinction…

Differential Geometry · Mathematics 2018-04-09 Valentino Tosatti , Yuguang Zhang

Given a seven-element set $X = \{1,2,3,4,5,6,7\}$, there are 30 ways to define a Fano plane on it. Let us call a line of such Fano plane, that is to say an unordered triple from $X$, ordinary or defective according as the sum of two smaller…

Combinatorics · Mathematics 2016-08-24 Metod Saniga

Libgober and Wood proved that the Chern number $c_{1}c_{n-1}$ of a $n$-dimensional compact complex manifold can be determined by its Hirzebruch $\chi_{y}$-genus. Inspired by the idea of their proof, we show that, for compact, spin,…

Differential Geometry · Mathematics 2018-10-18 Ping Li

We propose a method of measuring topological invariants of a photonic crystal through phase spectroscopy. We show how the Chern numbers can be deduced from the winding numbers of the reflection coefficient phase. An explicit proof of…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 A. V. Poshakinskiy , A. N. Poddubny , M. Hafezi

In this paper, we investigate manifolds for which the curvature of the second kind (following the terminology of Nishikawa) satisfies certain positivity conditions. Our main result settles Nishikawa's conjecture that manifolds for which the…

Differential Geometry · Mathematics 2026-01-23 Matthew Gursky , Xiaodong Cao , Hung Tran

Let X be a complex Fano manifold of arbitrary dimension, and D a prime divisor in X. We consider the image H of N_1(D) in N_1(X) under the natural push-forward of 1-cycles. We show that the codimension c of H in N_1(X) is at most 8.…

Algebraic Geometry · Mathematics 2011-12-21 C. Casagrande

The symmetric projective varieties of rank one are all smooth and Fano by a classic result of Akhiezer. We classify the locally factorial (respectively smooth) projective symmetric $G$-varieties of rank 2 which are Fano. When $G$ is…

Algebraic Geometry · Mathematics 2010-12-22 Alessandro Ruzzi

Following a suggestion in a footnote of the paper \cite {Fa} by Fano, we give a direct proof of the fact that one of the two Fano threefolds of maximal degree 72 in $\p^{38}$ is isomorphic to the anticanonically embedded weighted projective…

Algebraic Geometry · Mathematics 2023-06-12 Ciro Ciliberto

Generalising a classical theorem by Ueno, we prove structure results for manifolds with nef or semiample cotangent bundle.

Algebraic Geometry · Mathematics 2017-11-07 Andreas Höring

Steprans provided a characterization of betaN\N in the aleph_2-Cohen model that is much in the spirit of Parovicenko's characterization of this space under CH. A variety of the topological results established in the Cohen model can be…

General Topology · Mathematics 2014-01-15 Alan Dow , Klaas Pieter Hart

We study complex projective manifolds X that admit surjective endomorphisms f:X->X of degree at least two. In case f is etale, we prove structure theorems that describe X. In particular, a rather detailed description is given if X is a…

Algebraic Geometry · Mathematics 2007-06-22 Marian Aprodu , Stefan Kebekus , Thomas Peternell

Curves of low genus on a surface carry important informations on that surface. We study the Fano surfaces of lines of cubic threefolds that contain 12 or 30 elliptic curves. We determine their Picard number and compute a basis of the…

Algebraic Geometry · Mathematics 2010-02-05 Xavier Roulleau