2021

最新文章

• Ergodicity and type of nonsingular Bernoulli actions AI翻译
  作者：Bjorklund, Michael; Kosloff, Zemer; Vaes, Stefaan
  作者单位：Chalmers University of Technology; Hebrew University of Jerusalem; KU Leuven
  摘要：We determine the Krieger type of nonsingular Bernoulli actions G curved right arrow Pi(g is an element of G)({0,1},mu(g)). When G is abelian, we do this for arbitrary marginal measures mu(g). We prove in particular that the action is never of type II infinity if G is abelian and not locally finite, answering Krengel's question for G=Z. When G is locally finite, we prove that type II infinity does arise. For arbitrary countable groups, we assume that the marginal measures stay away from 0 and 1...
• Groups with decidable word problem that do not embed in groups with decidable conjugacy problem AI翻译
  作者：Darbinyan, Arman
  作者单位：Texas A&M University System; Texas A&M University College Station
  摘要：We show the existence of finitely presented torsion-free groups with decidable word problem that cannot be embedded in any finitely generated group with decidable conjugacy problem. This answers a well-known question of Collins from the early 1970's.
• Proof of the K(π, 1) conjecture for affine Artin groups AI翻译
  作者：Paolini, Giovanni; Salvetti, Mario
  作者单位：University of Fribourg; California Institute of Technology; University of Pisa
  摘要：We prove the K(pi,1) conjecture for affine Artin groups: the complexified complement of an affine reflection arrangement is a classifying space. This is a long-standing problem, due to Arnol'd, Pham, and Thom. Our proof is based on recent advancements in the theory of dual Coxeter and Artin groups, as well as on several new results and constructions. In particular: we show that all affine noncrossing partition posets are EL-shellable; we use these posets to construct finite classifying spaces ...
• Masur-Veech volumes and intersection theory on moduli spaces of Abelian differentials (vol 222, pg 283, 2020) AI翻译
  作者：Chen, Dawei; Moeller, Martin; Sauvaget, Adrien; Zagier, Don
  作者单位：Boston College; Goethe University Frankfurt; Centre National de la Recherche Scientifique (CNRS); CNRS - National Institute for Mathematical Sciences (INSMI); CY Cergy Paris Universite
  摘要：A Correction to this paper has been published: https://doi.org/10.1007/s00222-020-00969-4
• Mixing solutions for the Muskat problem AI翻译
  作者：Castro, A.; Cordoba, D.; Faraco, D.
  作者单位：Autonomous University of Madrid; Consejo Superior de Investigaciones Cientificas (CSIC); CSIC - Instituto de Ciencias Matematicas (ICMAT); Universidad Carlos III de Madrid; CSIC - Instituto de Ciencia de Materiales de Madrid (ICMM); Complutense University of Madrid; Autonomous University of Madrid
  摘要：We prove the existence of mixing solutions of the incompressible porous media equation for all Muskat type H-5 initial data in the fully unstable regime. The proof combines convex integration, contour dynamics and a basic calculus for non smooth semiclassical type pseudodifferential operators which is developed.
• The local fundamental group of a Kawamata log terminal singularity is finite AI翻译
  作者：Braun, Lukas
  作者单位：University of Freiburg
  摘要：We prove a conjecture of Kollar stating that the local fundamental group of a klt singularity x is finite. In fact, we prove a stronger statement, namely that the fundamental group of the smooth locus of a neighbourhood of x is finite. We call this the regional fundamental group. As the proof goes via a local-to-global induction, we simultaneously confirm finiteness of the orbifold fundamental group of the smooth locus of a weakly Fano pair.
• The logarithmic gauged linear sigma model AI翻译
  作者：Chen, Qile; Janda, Felix; Ruan, Yongbin
  作者单位：Boston College; University of Notre Dame; Zhejiang University
  摘要：We introduce the notion of log R-maps, and develop a proper moduli stack of stable log R-maps in the case of a hybrid gauged linear sigma model. Two virtual cycles (canonical and reduced) are constructed for these moduli stacks. The main results are two comparison theorems relating the reduced virtual cycle to the cosection localized virtual cycle, as well as the reduced virtual cycle to the canonical virtual cycle. This sets the foundation of a new technique for computing higher genus Gromov-...
• Supersingular K3 surfaces are unirational (vol 200, pg 979, 2015) AI翻译
  作者：Liedtke, Christian
  作者单位：Technical University of Munich
  摘要：As was pointed out by Bragg and Lieblich
• A Dichotomy for the Weierstrass-type functions AI翻译
  作者：Ren, Haojie; Shen, Weixiao
  作者单位：Fudan University; Fudan University
  摘要：For a real analytic periodic function phi : R -> R, an integer b >= 2 and lambda is an element of (1/b, 1), we prove the following dichotomy for the Weierstrass-type function W(x) = Sigma(n >=)0 lambda(n)phi(b(n)x): Either W(x) is real analytic, or the Hausdorff dimension of its graph is equal to 2 + log(b) lambda. Furthermore, given b and phi, the former alternative only happens for finitely many lambda unless phi is constant.
• A counterexample to vanishing conjectures for negative K-theory AI翻译
  作者：Neeman, Amnon
  作者单位：Australian National University
  摘要：In a 2006 article Schlichting conjectured that the negative K-theory of any abelian category must vanish. This conjecture was generalized in a 2019 article by Antieau, Gepner and Heller, who hypothesized that the negative K-theory of any category with a bounded t-structure must vanish. Both conjectures will be shown to be false.