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We define and study Jacobians of Hodge structures with weight greater than 1. Jacobians of weight 2 naturally come up in the context of the Brauer group and the Tate conjecture. They were previously studied in a special case by Beauville in…

Algebraic Geometry · Mathematics 2025-09-03 Sheela Devadas , Max Lieblich

We define triangulated factorization systems on triangulated categories, and prove that a suitable subclass thereof (the normal triangulated torsion theories) corresponds bijectively to $t$-structures on the same category. This result is…

Category Theory · Mathematics 2018-02-13 Fosco Loregian , Simone Virili

We show that every separable simple tracially approximately divisible $C^*$-algebra has strict comparison, is either purely infinite, or has stable rank one. As a consequence, we show that every (non-unital) finite simple ${\cal Z}$-stable…

Operator Algebras · Mathematics 2021-09-07 Xuanlong Fu , Kang Li , Huaxin Lin

We introduce and compute the class of a number of effective divisors on the moduli space of stable maps $\bar M_{0,0}(P^{r},d)$, which, for small d, provide a good understanding of the extremal rays and the stable base locus decomposition…

Algebraic Geometry · Mathematics 2009-05-19 Dawei Chen , Izzet Coskun , Charley Crissman

New birational invariants for a projective manifold are defined by using Lawson homology. These invariants can be highly nontrivial even for projective threefolds. Our techniques involve the weak factorization theorem of Wlodarczyk and…

Algebraic Geometry · Mathematics 2007-05-23 Wenchuan Hu

A purely algebraic method is devised in order to recover Slavnov-Taylor identities (STI), broken by intermediate renormalization. The counterterms are evaluated order by order in terms of finite amplitudes computed at zero external momenta.…

High Energy Physics - Theory · Physics 2009-10-31 Ruggero Ferrari , Pietro Antonio Grassi , Andrea Quadri

We construct a birational invariant for certain algebraic group actions. We use this invariant to classify linear representations of finite abelian groups up to birational equivalence, thus answering, in a special case, a question of E. B.…

Algebraic Geometry · Mathematics 2007-05-23 Zinovy Reichstein , Boris Youssin

Let $\mathbb{K}$ be an algebraically closed field of characteristic 0. A finite dimensional Lie algebra $\mathfrak{g}$ over $\mathbb{K}$ is said to be stable if there exists a linear form $g\in\mathfrak{g}^{*}$ and a Zariski open subset in…

Representation Theory · Mathematics 2013-05-08 Kais Ammari

We study the rationality properties of the moduli space $\mathcal{A}_g$ of principally polarised abelian $g$-folds over $\mathbb{Q}$ and apply the results to arithmetic questions. In particular we show that any principally polarised abelian…

Algebraic Geometry · Mathematics 2025-03-26 Daniel Loughran , Gregory Sankaran

We classify stably/retract rational norm one tori in dimension $p-1$ where $p$ is a prime number and in dimension up to ten with some minor exceptions.

Algebraic Geometry · Mathematics 2019-05-27 Akinari Hoshi , Aiichi Yamasaki

For any prime number $p$ and field $k$, we characterize the $p$-retract rationality of an algebraic $k$-torus in terms of its character lattice. We show that a $k$-torus is retract rational if and only if it is $p$-retract rational for…

Algebraic Geometry · Mathematics 2020-02-19 Federico Scavia

We define topological orthoalgebras (TOAs) and study their properties. While every topological orthomodular lattice is a TOA, the lattice of projections of a Hilbert space is an example of a lattice-ordered TOA that is not a toplogical…

Rings and Algebras · Mathematics 2009-11-10 Alexander Wilce

We establish a general result about extending a right invertible row over a Banach algebra to an invertible matrix. This is applied to the computation of right topological stable rank of a split exact sequence. We also introduce a…

Operator Algebras · Mathematics 2014-02-26 Kenneth R. Davidson , You Qing Ji

We introduce type-theoretic algebraic weak factorisation systems and show how they give rise to homotopy-theoretic models of Martin-L\"of type theory. This is done by showing that the comprehension category associated to a type-theoretic…

Category Theory · Mathematics 2022-06-30 Nicola Gambino , Marco Federico Larrea

We study normal compact K\"ahler spaces whose rational cohomology ring is isomorphic to that of a complex torus. We call them rational cohomology tori. We classify, up to dimension three, those with rational singularities. We then give…

Algebraic Geometry · Mathematics 2017-03-29 Olivier Debarre , Zhi Jiang , Martí Lahoz , William F. Sawin

We set up a generalization of ubiquitous one-parameter families in algebraic geometry and their use for stability theories ([GIT, HL, AHLH]) to families over toric varieties and their analytic analogues. The language allows us to…

Algebraic Geometry · Mathematics 2025-02-20 Yuji Odaka

We show that two C*-algebraic noncommutative tori are strongly Morita equivalent if and only if they have isomorphic ordered K_0-groups and centers, extending N. C. Phillips's result in the case that the algebras are simple. This is also…

Operator Algebras · Mathematics 2007-05-23 George A. Elliott , Hanfeng Li

Using Mackey functors, we provide a general framework for classifying torsors of algebraic tori in terms of Brauer groups of finite field extensions of the base field. This generalizes Blunk's description of the tori associated to del Pezzo…

Algebraic Geometry · Mathematics 2025-09-12 Alexander Duncan , Pankaj Singh

For a finite-dimensional gentle algebra, it is already known that the functorially finite torsion classes of its category of finite-dimensional modules can be classified using a combinatorial interpretation, called maximal non-crossing sets…

Representation Theory · Mathematics 2020-09-23 Aaron Chan , Laurent Demonet

We present a classification theorem for a class of unital simple separable amenable ${\cal Z}$-stable $C^*$-algebras by the Elliott invariant. This class of simple $C^*$-algebras exhausts all possible Elliott invariant for unital stably…

Operator Algebras · Mathematics 2015-11-17 Guihua Gong , Huaxin Lin , Zhuang Niu