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We develop the novel machinery of smooth approximations, and apply it to confirm the CSP dichotomy conjecture for first-order reducts of the random tournament, various homogeneous graphs including the random graph, and for expansions of the…

Logic in Computer Science · Computer Science 2021-06-08 Antoine Mottet , Michael Pinsker

We describe some methods to compute fundamental groups, (co)homology, and irregularity of semi-log-canonical surfaces. As an application, we show that there are exactly two irregular Gorenstein stable surfaces with $K^2=1$, both of which…

Algebraic Geometry · Mathematics 2014-04-15 Marco Franciosi , Rita Pardini , Sönke Rollenske

We give simple upper bounds for rational sectional category and use them to compute invariants of the type of Farber's topological complexity of rational spaces. In particular we show that the sectional category of formal morphisms reaches…

Algebraic Topology · Mathematics 2015-03-10 J. G. Carrasquel-Vera

Greuel, Lossen and Shustin gave a general sufficient numerical condition for the T-smoothness (smoothness and expected dimension) of equisingular families of plane curves. This condition involves a new invariant \gamma for plane curve…

Algebraic Geometry · Mathematics 2009-07-28 Thomas Keilen , Christoph Lossen

A Theorem due to Guillemin and Sternberg about geometric quantization of Hamiltonian actions of compact Lie groups $G$ on compact Kaehler manifolds says that the dimension of the $G$-invariant subspace is equal to the Riemann-Roch number of…

alg-geom · Mathematics 2008-02-03 Eckhard Meinrenken

We study the moduli space of $G_2$-instantons on (projectively) flat bundles over torsion-free $G_2$-orbifolds. We prove that the moduli space is compact and smooth at the irreducible locus after adding small and generic holonomy…

Differential Geometry · Mathematics 2023-04-04 Langte Ma

A thorough classification of the topologies of compact homogeneous universes is given except for the hyperbolic spaces, and their global degrees of freedom are completely worked out. To obtain compact universes, spatial points are…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Tatsuhiko Koike , Masayuki Tanimoto , Akio Hosoya

We prove a surgery formula for the ordinary Seiberg-Witten invariants of smooth $4$-manifolds with $b_1 =1$. Our formula expresses the Seiberg-Witten invariants of the manifold after the surgery, in terms of the original Seiberg-Witten…

Geometric Topology · Mathematics 2024-09-05 Haochen Qiu

We introduce a new generalization of Gompf nuclei and give applications. We construct infinitely many exotic smooth structures for a large class of compact 4-manifolds with boundary, regarding topological invariants. We prove that a large…

Geometric Topology · Mathematics 2012-02-17 Kouichi Yasui

We prove that for every natural number k there are simply connected topological four-manifolds which have at leat k distinct smooth structures supporting Einstein metrics, and also have infinitely many distinct smooth structures not…

Geometric Topology · Mathematics 2007-05-23 V. Braungardt , D. Kotschick

We determine the structure of certain moduli spaces of ideal sheaves by generalizing an earlier result of the first author. As applications, we compute the (virtual) Hodge polynomials of these moduli space, and calculate the…

Algebraic Geometry · Mathematics 2016-09-07 Sheldon Katz , Wei-Ping Li , Zhenbo Qin

Kontsevich's characteristic classes are invariants of framed smooth fiber bundles with homology sphere fibers. It was shown by Watanabe that they can be used to distinguish smooth $S^4$-bundles that are all trivial as topological fiber…

Geometric Topology · Mathematics 2026-03-11 Xujia Chen

When two smooth manifold bundles over the same base are fiberwise tangentially homeomorphic, the difference is measured by a homology class in the total space of the bundle. We call this the relative smooth structure class. Rationally and…

K-Theory and Homology · Mathematics 2012-04-10 Sebastian Goette , Kiyoshi Igusa , Bruce Williams

The space of $C^1$ cubic Clough-Tocher splines is a classical finite element approximation space over triangulations for solving partial differential equations. However, for such a space there is no B-spline basis available, which is a…

Numerical Analysis · Mathematics 2023-05-04 Jan Grošelj , Hendrik Speleers

For a regular pair $(X,Y)$ of schemes of pure codimension 1 on which 2 is invertible, we consider quadric bundles on $X$ which are nondegenerate on $X-Y$, but are minimally degenerate on $Y$. We give a formula for the behaviour of the…

Algebraic Geometry · Mathematics 2013-04-25 Saurav Bhaumik , Nitin Nitsure

In this review, novel non-standard techniques for the computation of cohomology classes on toric varieties are summarized. After an introduction of the basic definitions and properties of toric geometry, we discuss a specific computational…

High Energy Physics - Theory · Physics 2011-09-08 Ralph Blumenhagen , Benjamin Jurke , Thorsten Rahn

We construct quantum invariants of balanced sutured 3-manifolds with a $Spin^{c}$ structure out of an involutive (possibly non-unimodular) Hopf superalgebra $H$. If $H$ is the Borel subalgebra of $U_{q}(\mathfrak{gl}(1|1))$, we show that…

Geometric Topology · Mathematics 2023-06-22 Daniel López Neumann

We compute the cohomological invariants of $\mathcal{H}_g$, the moduli stack of smooth hyperelliptic curves, for every odd $g$.

Algebraic Geometry · Mathematics 2020-07-21 Andrea Di Lorenzo

A smooth cuboid can be identified with a $3\times 3$ matrix of linear forms, with coefficients in a field $K$, whose determinant describes a smooth cubic in the projective plane. To each such matrix one can associate a group scheme over…

Group Theory · Mathematics 2025-04-23 Joshua Maglione , Mima Stanojkovski

We extend some known results from smooth dynamical systems to the category of Lipschitz homeomorphisms of compact metric spaces. We consider dynamical properties as robust expansiveness and structural stability allowing Lipschitz…

Dynamical Systems · Mathematics 2014-09-26 Alfonso Artigue