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Let $S_g$ denote the closed orientable surface of genus $g$. We construct exponentially many mapping class group orbits of collections of $2g+1$ simple closed curves on $S_g$ which pairwise intersect exactly once, extending a result of the…

Geometric Topology · Mathematics 2015-02-03 Tarik Aougab , Jonah Gaster

We give two proofs that appropriately defined congruence subgroups of the mapping class group of a surface with punctures/boundary have enormous amounts of rational cohomology in their virtual cohomological dimension. In particular we give…

Geometric Topology · Mathematics 2022-02-21 Tara Brendle , Nathan Broaddus , Andrew Putman

Let S be a Dedekind scheme with field of functions K. We show that if X_K is a smooth connected proper curve of positive genus over K, then it admits a N\'eron model over S, i.e., a smooth separated model of finite type satisfying the usual…

Algebraic Geometry · Mathematics 2016-09-29 Qing Liu , Jilong Tong

Let $S$ be a hyperbolic oriented Riemann surface of finite type. The main purpose of this paper is to show that non-trivial geometric intersection between closed curves on $S$ is detected by some symplectic submodules they naturally…

Algebraic Topology · Mathematics 2024-06-14 Marco Boggi , Pavel Zalesskii

We give a very short proof of two Theorems, whose content is outlined in the title, and where $\Pi_g$ is the fundamental group of a compact complex curve of genus $g$: (1) Theorem 2.1 of the irrational pencil in the profinite version,…

Algebraic Geometry · Mathematics 2025-12-23 Fabrizio Catanese , appendix by Pavel Zalesskii

A proof of freeness of the commutator subgroup of the fundamental group of a smooth irreducible affine curve over a countable algebraically closed field of nonzero characteristic. A description of the abelianizations of the fundamental…

Algebraic Geometry · Mathematics 2007-05-23 Manish Kumar

We give a complete description of finite braid group orbits in Aff(C)-character varieties of the punctured Riemann sphere. This is performed thanks to a coalescence procedure and to the theory of finite complex reflection groups. We then…

Geometric Topology · Mathematics 2016-11-03 Gaël Cousin , Delphine Moussard

We show that all GGS-groups with non-constant defining vector satisfy the congruence subgroup property. This provides, for every odd prime $p$, many examples of finitely generated, residually finite, non-torsion groups whose profinite…

Group Theory · Mathematics 2024-08-27 Gustavo A. Fernández-Alcober , Alejandra Garrido , Jone Uria-Albizuri

Let Mod(S) be the extended mapping class group of a surface S. For S the twice-punctured torus, we show that there exists an isomorphism of finite index subgroups of Mod(S) which is not the restriction of an inner automorphism. For S a…

Geometric Topology · Mathematics 2008-11-15 Jason Behrstock , Dan Margalit

We prove that curve complexes of surfaces are finitely rigid: for every orientable surface S of finite topological type, we identify a finite subcomplex X of the curve complex C(S) such that every locally injective simplicial map from X…

Geometric Topology · Mathematics 2012-07-25 Javier Aramayona , Christopher J. Leininger

We give large families of Shimura curves defined by congruence conditions, all of whose twists lack $p$-adic points for some $p$. For each such curve we give analytically large families of counterexamples to the Hasse principle via the…

Number Theory · Mathematics 2015-11-10 James Stankewicz

Let L be a finite-dimensional semisimple Lie algebra with a non-degenerate invariant bilinear form, \sigma an elliptic automorphism of L leaving the form invariant, and A a \sigma-invariant reductive subalgebra of L, such that the…

Representation Theory · Mathematics 2017-01-18 Victor G. Kac , Pierluigi Moseneder Frajria , Paolo Papi

Let K be the subgroup of the extended mapping class group, Mod(S), generated by Dehn twists about separating curves. Assuming that S is a closed, orientable surface of genus at least 4, we confirm a conjecture of Farb that Comm(K), Aut(K)…

Geometric Topology · Mathematics 2014-11-11 Tara E Brendle , Dan Margalit

The Pappas-Rapoport coherence conjecture, proved by Zhu, states that the dimensions of spaces of sections of certain line bundles coincide. The two sides of the equality correspond to the line bundles on spherical Schubert varieties in the…

Representation Theory · Mathematics 2026-04-06 Evgeny Feigin , an appendix in collaboration with Andrey Karenskih

We develop a framework for function classes generated by parametric ridge kernels: one-dimensional kernels composed with affine projections and averaged over a parameter measure. The induced kernels are positive definite, and the resulting…

Functional Analysis · Mathematics 2025-08-26 James Tian

Let $\MS_g$ be the moduli space of stable holomorphic vector bundles of rank 2 and fixed determinant of odd degree over a smooth complex projective curve of genus $g$. This paper proves various properties of the rational cohomology ring…

alg-geom · Mathematics 2008-02-03 A. D. King , P. E. Newstead

We give conceptual proofs of some results on the automorphism group of an Enriques surface X, for which only computational proofs have been available. Namely, there is an obvious upper bound on the image of Aut(X) in the isometry group of…

Algebraic Geometry · Mathematics 2018-04-04 Daniel Allcock

We propose graph kernels based on subgraph matchings, i.e. structure-preserving bijections between subgraphs. While recently proposed kernels based on common subgraphs (Wale et al., 2008; Shervashidze et al., 2009) in general can not be…

Machine Learning · Computer Science 2012-07-03 Nils Kriege , Petra Mutzel

We introduce the fiberwise Bergman kernel for a flat family of polarized varieties over a Riemann surface, which extends the classical Bergman kernel defined on the reduced fibers. We establish the continuity of the fiberwise Bergman kernel…

Complex Variables · Mathematics 2023-04-28 Linsheng Wang , Shengxuan Zhou

Let $\mathbb{G}$ be any Carnot group. We prove that, if a subset of $\mathbb{G}$ is contained in a rectifiable curve, then it satisfies Peter Jones' geometric lemma with some natural modifications. We thus prove one direction of the…

Metric Geometry · Mathematics 2019-09-16 Vasileios Chousionis , Sean Li , Scott Zimmerman