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We describe the extension of normal iteration strategies with appropriate condensation properties to strategies for stacks of normal trees, with full normalization. Given a regular uncountable cardinal $\Omega$ and an…

Logic · Mathematics 2024-03-19 Farmer Schlutzenberg

Let $X$ be a smooth projective variety defined over an algebraically closed field of positive characteristic $p$ whose tangent bundle is nef. We prove that $X$ admits a smooth morphism $X \to M$ such that the fibers are Fano varieties with…

Algebraic Geometry · Mathematics 2020-12-18 Akihiro Kanemitsu , Kiwamu Watanabe

Let (S, B) be the log pair associated with a projective completion of a smooth quasi-projective surface V . Under the assumption that the boundary B is irreducible, we obtain an algorithm to factorize any automorphism of V into a sequence…

Algebraic Geometry · Mathematics 2016-10-25 Adrien Dubouloz , Stéphane Lamy

We introduce the notion of a multi-fan. It is a generalization of that of a fan in the theory of toric variety in algebraic geometry. Roughly speaking a toric variety is an algebraic variety with an action of algebraic torus of the same…

Symplectic Geometry · Mathematics 2007-05-23 Akio Hattori , Mikiya Masuda

We present a new approach to construct $T$-equivariant flat toric degenerations of flag varieties and spherical varieties, combining ideas coming from the theory of Newton-Okounkov bodies with ideas originally stemming from PBW-filtrations.…

Algebraic Geometry · Mathematics 2017-10-03 Xin Fang , Ghislain Fourier , Peter Littelmann

In this paper, we introduce the notion of an admissible partition of a simplicial polyhedral fan and define the category of a partitioned fan as a generalisation of the $\tau$-cluster morphism category of a finite-dimensional algebra. This…

Representation Theory · Mathematics 2025-02-26 Maximilian Kaipel

We continue the approach toward a purely combinatorial "virtual" intersection cohomology for possibly non-rational fans, based on our investigation of equivariant intersection cohomology for toric varieties (see math.AG/9904159).…

Algebraic Geometry · Mathematics 2007-05-23 Gottfried Barthel , Jean-Paul Brasselet , Karl-Heinz Fieseler , Ludger Kaup

We investigate the equivariant intersection cohomology of a toric variety. Considering the defining fan of the variety as a finite topological space with the subfans being the open sets (that corresponds to the "toric" topology given by the…

Algebraic Geometry · Mathematics 2007-05-23 Gottfried Barthel , Jean-Paul Brasselet , Karl-Heinz Fieseler , Ludger Kaup

We announce a factorization result for equivariant birational morphisms between toric 4-folds whose source is Fano: such a morphism is always a composite of blow-ups along smooth invariant centers. Moreover, we show with a counterexample…

Algebraic Geometry · Mathematics 2007-05-23 Cinzia Casagrande

Using tropical geometry we propose a mirror construction for monomial degenerations of Calabi-Yau varieties in toric Fano varieties. The construction reproduces the mirror constructions by Batyrev for Calabi-Yau hypersurfaces and by Batyrev…

Algebraic Geometry · Mathematics 2007-09-03 Janko Boehm

We present cut and project formalism based on measures and continuous weight functions of sufficiently fast decay. The emerging measures are strongly almost periodic. The corresponding dynamical systems are compact groups and homomorphic…

Dynamical Systems · Mathematics 2008-08-28 Daniel Lenz , Christoph Richard

Suppose that $C\subset\mathbb P^2$ is a general enough nodal plane curve of degree $>2$, $\nu\colon \hat C\to C$ is its normalization, and $\pi\colon \hat C\to\mathbb P^1$ is a finite morphism simply ramified over the same set of points as…

Algebraic Geometry · Mathematics 2014-01-22 Yu. Burman , Serge Lvovski

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

The tropicalization of an algebraic variety X is a combinatorial shadow of X, which is sensitive to a closed embedding of X into a toric variety. Given a good embedding, the tropicalization can provide a lot of information about X. We…

Algebraic Geometry · Mathematics 2020-06-30 Philipp Jell

We investigate the strong and the weak convergence properties of the following gradient projection algorithm with Tikhonov regularizing term \[ x_{n+1}=P_{Q}(x_{n}-\gamma_{n}\nabla f(x_{n})-\gamma_{n}\alpha_{n}\nabla \phi (x_{n})), \] where…

Optimization and Control · Mathematics 2019-10-18 Ramzi May

This paper proves that every projective toric variety is the fine moduli space for stable representations of an appropriate bound quiver. To accomplish this, we study the quiver $Q$ with relations $R$ corresponding to the finite-dimensional…

Algebraic Geometry · Mathematics 2010-03-15 Alastair Craw , Gregory G. Smith

Kawakami and the author showed that a projective variety with an int-amplified endomorphism of degree invertible in the base field satisfies Bott vanishing. That was a new way to analyze which varieties have nontrivial endomorphisms. In…

Algebraic Geometry · Mathematics 2025-02-12 Burt Totaro

We propose an extended full-waveform inversion formulation that includes general convex constraints on the model. Though the full problem is highly nonconvex, the overarching optimization scheme arrives at geologically plausible results by…

Optimization and Control · Mathematics 2016-08-23 Ernie Esser , Lluis Guasch , Tristan van Leeuwen , Aleksandr Y. Aravkin , Felix J. Herrmann

Parallel and cyclic projection algorithms are proposed for minimizing the sum of a finite family of convex functions over the intersection of a finite family of closed convex subsets of a Hilbert space. These algorithms are of…

Optimization and Control · Mathematics 2019-01-08 Hong-Kun Xu , Vera Roshchina

This paper is devoted to the study of a newly introduced tool, projectional coderivatives and the corresponding calculus rules in finite dimensions. We show that when the restricted set has some nice properties, more specifically, is a…

Optimization and Control · Mathematics 2024-10-24 Wenfang Yao , Kaiwen Meng , Minghua Li , Xiaoqi Yang