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Using theory of props we prove a formality theorem associated with universal quantizations of (strongly homotopy) Lie bialgebras.

Quantum Algebra · Mathematics 2016-01-29 S. A. Merkulov

In this note we prove the Borel Conjecture for closed, irreducible and sufficiently collapsed three-dimensional Alexandrov spaces. We also pose several questions related to characterization of fundamental groups of three-dimensional…

Metric Geometry · Mathematics 2020-11-26 Noé Bárcenas , Jesús Núñez-Zimbrón

We obtain density theorems for cuspidal automorphic representations of $\text{GL}_n$ over $\mathbb{Q}$ which fail the generalized Ramanujan conjecture at some place. We depart from previous approaches based on Kuznetsov-type trace formulae,…

Number Theory · Mathematics 2024-08-27 Jared Duker Lichtman , Alexandru Pascadi

In this paper, we prove that the deformation theory of an object in an $n$-category is controlled by the its $n$-fold endomorphism algebra. This recovers Lurie's results on deforming objects and categories. We also generalize a previous…

Algebraic Geometry · Mathematics 2025-07-04 Fei Yu Chen

We prove the unbounded denominators conjecture in the theory of noncongruence modular forms for finite index subgroups of SL_2(Z). Our result includes also Mason's generalization of the original conjecture to the setting of vector-valued…

Number Theory · Mathematics 2024-09-18 Frank Calegari , Vesselin Dimitrov , Yunqing Tang

The main result of the paper is a boundedness for $n$-complements on algebraic surfaces. In addition, applications of this theorem to a classification of log Del Pezzo surfaces and of birational contractions for 3-folds are formulated.

alg-geom · Mathematics 2007-05-23 V. V. Shokurov

In this paper we prove that any Riemannian surface, with no restriction of curvature at all, can be decomposed into blocks belonging just to some of these types: generalized Y-pieces, generalized funnels and halfplanes.

Differential Geometry · Mathematics 2008-06-03 Ana Portilla , Jose M. Rodriguez , Eva Touris

With any hyper-K\"ahler variety $K$ of generalized Kummer type is associated via Hodge theory a K3 surface $S_K$. We show how they are related geometrically through a moduli space of sheaves on $S_K$. As a consequence, building…

Algebraic Geometry · Mathematics 2025-11-26 Salvatore Floccari

We study some formality criteria for differential graded algebras over differential graded operads. This unifies and generalizes other known approaches like the ones by Manetti and Kaledin. In particular, we construct general operadic…

Quantum Algebra · Mathematics 2020-05-12 Valerio Melani , Marcel Rubió

We study the degeneration relations on the varieties of associative and Lie algebra structures on a fixed finite dimensional vector space and give a description of them in terms of Gerstenhaber formal deformations. We use this result to…

Rings and Algebras · Mathematics 2019-07-31 Sergio Chouhy

We report on recent results concerning the construction of curves on K3 surfaces: the proof of the Tate conjecture for K3 surfaces in odd characteristic (after Maulik, Charles and Madapusi Pera), and the construction of infinitely many…

Algebraic Geometry · Mathematics 2019-11-11 Olivier Benoist

The primary aim of this essay, drawn from the author's MMath dissertation at Oxford, is to present and explain Kontsevich's formality theorem. The first two sections introduce the main topic. Sections 3 and 4 discuss Hochschild…

Quantum Algebra · Mathematics 2025-09-19 Haiqi Wu

In this paper we set-up a general framework for a formal deformation theory of Dirac structures. We give a parameterization of formal deformations in terms of two-forms obeying a cubic equation. The notion of equivalence is discussed in…

Quantum Algebra · Mathematics 2009-11-11 Frank Keller , Stefan Waldmann

We state the analogs of Kontsevich's formality conjecture for Hochschild and cyclic chains, as well as their

Quantum Algebra · Mathematics 2007-05-23 Boris Tsygan

We prove that very general, dual Gushel-Mukai surfaces are not isomorphic, though derived and L-equivalent. We use this result to study two semiorthogonal decompositions for a family of Fano fourfolds of K3 type, answering a question by…

Algebraic Geometry · Mathematics 2025-12-18 Yulieth Prieto-Montañez , Ian Selvaggi

In this paper, we prove the K- and L-theoretical Isomorphism Conjecture for Baumslag-Solitar groups with coefficients in an additive category.

Algebraic Topology · Mathematics 2014-05-27 Tom Farrell , Xiaolei Wu

It is conjectured that there exist finitely many isomorphism classes of simple endomorphism algebras of abelian varieties of GL_2-type over \Q of bounded dimension. We explore this conjecture when particularized to quaternion endomorphism…

Number Theory · Mathematics 2011-11-10 Nils Bruin , E. Victor Flynn , Josep Gonzalez , Victor Rotger

Motivated by the problem of transverse deformation quantization of foliated manifolds, we describe a quantization of Dirac structures (more precisely, of those that are formal deformations of regular ones) to stacks of algebroids in the…

Quantum Algebra · Mathematics 2007-05-23 Pavol Severa

We prove the homological mirror symmetry conjecture of Kontsevich for K3 surfaces in the following form: The Fukaya category of a projective K3 surface is equivalent to the derived category of coherent sheaves on the mirror, which is a K3…

Symplectic Geometry · Mathematics 2025-03-10 Paul Hacking , Ailsa Keating

We prove the KKV conjecture expressing Gromov-Witten invariants of K3 surfaces in terms of modular forms. Our results apply in every genus and for every curve class. The proof uses the Gromov-Witten/Pairs correspondence for K3-fibered…

Algebraic Geometry · Mathematics 2017-05-24 R. Pandharipande , R. P. Thomas