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Related papers: Yu. M. Smirnov's General Equivariant Shape Theory

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We solve a long-standing open problem, formulated by Krasner in the 1950's, in the context of Polish (i.e. separable complete) ultrametric spaces by providing a characterization of their isometry groups using suitable forms of generalized…

Logic · Mathematics 2026-03-20 Riccardo Camerlo , Alberto Marcone , Luca Motto Ros

Equivariant compactifications of reductive groups can be described by combinatorial data. On the other hand, equivariant compactifications of the additive group G^n_a are more complicated in at least two respects. First, they often admit…

Algebraic Geometry · Mathematics 2007-05-23 Brendan Hassett , Yuri Tschinkel

Hrushovski proved the Lie model theorem in full generality with model theoretic methods. The theorem states that for every approximate group there exists a generalized definable locally compact model, which, simplifying, is a…

Logic · Mathematics 2025-12-17 Beatrice Degasperi

Suggested theory involves a drastic revision of a role of local internal symmetries in physical concept of curved geometry. Under the reflection of fields and their dynamics from Minkowski to Riemannian space a standard gauge principle of…

General Relativity and Quantum Cosmology · Physics 2007-05-23 G. T. Ter-Kazarian

Two non-discrete Hausdorff group topologies $\tau, \delta$ on a group $G$ are called {\it transversal} if the least upper bound $\tau\vee \delta$ of $\tau$ and $\delta$ is the discrete topology. In this paper, we discuss the existence of…

Group Theory · Mathematics 2020-04-14 Fucai Lin , Zhongbao Tang

We extend several techniques and theorems from geometric group theory so that they apply to geometric actions on arbitrary proper metric ARs (absolute retracts). A second way that we generalize earlier results is by eliminating freeness…

Geometric Topology · Mathematics 2018-01-09 Craig R. Guilbault , Molly A. Moran

We define equivariant homology theories using bordism of stratifolds with a G-action, where G is a discrete group. Stratifolds are a generalization of smooth manifolds which were introduced by Kreck. He defines homology theories using…

Algebraic Topology · Mathematics 2007-05-23 Julia Weber

In 2003, S.-s. Chern began a study of almost-complex structures on the 6-sphere, with the idea of exploiting the special properties of its well-known almost-complex structure invariant under the exceptional group $G_2$. While he did not…

Differential Geometry · Mathematics 2021-11-30 Robert L. Bryant

In this paper a new approach is derived in the context of shape theory. The implemented methodology is motivated in an open problem proposed in \citet{GM93} about the construction of certain shape density involving Euler hypergeometric…

Statistics Theory · Mathematics 2015-02-04 Francisco J. Caro-Lopera , José A. Díaz-García

The predictions of the Mirror Symmetry are extended in dimensions n>3 and are proven for projective complete intersections Calabi-Yau varieties. Precisely, we prove that the total collection of rational Gromov-Witten invariants of such…

Algebraic Geometry · Mathematics 2019-06-04 Sergey Barannikov

A novel selection principle was introduced by Dorantes-Aldama and Shakhmatov: a topological space $X$ is termed {\em selectively pseudocompact} if for any sequence $(U_n:n\in {\omega})$ of pairwise disjoint non-empty open sets of $X$, one…

General Topology · Mathematics 2025-10-21 István Juhász , Lajos Soukup , Zoltán Szentmiklóssy

The long-standing problem of the perfectness of the compactly supported equivariant homeomorphism group on a $G$-manifold (with one orbit type) is solved in the affirmative. The proof is based on an argument different than that for the case…

Differential Geometry · Mathematics 2011-04-20 Tomasz Rybicki

Twenty years ago Gromov asked about how large is the set of isomorphism classes of groups whose systolic area is bounded from above. This article introduces a new combinatorial invariant for finitely presentable groups called {\it…

Geometric Topology · Mathematics 2023-04-03 Ivan Babenko , Florent Balacheff , Guillaume Bulteau

Bounded cohomology of groups was first studied by Gromov in 1982. Since then it has sparked much research in Geometric Group Theory. However, it is notoriously hard to explicitly compute bounded cohomology, even for most basic…

Group Theory · Mathematics 2018-10-12 Nicolaus Heuer

Let G be a discrete group and let X be a G-finite, proper G-CW-complex. We prove that Kasparov's equivariant K-homology groups KK^G(C_0(X),\C) are isomorphic to the geometric equivariant K-homology groups of X that are obtained by making…

K-Theory and Homology · Mathematics 2012-10-12 Paul Baum , Nigel Higson , Thomas Schick

We study the geometry of universal embedding spaces for compact almost complex manifolds of a given dimension. These spaces are complex algebraic analogues of twistor spaces that were introduced by J-P. Demailly and H. Gaussier. Their…

Algebraic Geometry · Mathematics 2022-02-21 Gabriella Clemente

The quasispecies model introduced by Eigen in 1971 has close connections with the isometry group of the space of binary sequences relative to the Hamming distance metric. Generalizing this observation we introduce an abstract quasispecies…

Populations and Evolution · Quantitative Biology 2017-06-15 Yuri S. Semenov , Artem S. Novozhilov

We introduce a notion of topological M-theory and argue that it provides a unification of form theories of gravity in various dimensions. Its classical solutions involve G_2 holonomy metrics on 7-manifolds, obtained from a topological…

High Energy Physics - Theory · Physics 2008-11-26 Robbert Dijkgraaf , Sergei Gukov , Andrew Neitzke , Cumrun Vafa

We present a decomposition of rational twisted $G$-equivariant K-theory, $G$ a finite group, into cyclic group equivariant K-theory groups of fixed point spaces. This generalises the untwisted decomposition by Atiyah and Segal as well as…

K-Theory and Homology · Mathematics 2023-12-22 Tom Dove , Thomas Schick , Mario Velásquez

Starting with assumptions both simple and natural from "physical" point of view we present a direct construction of transformations preserving wide class of (anti)commutation relations which describe Euclidean/Minkowski superspace…

High Energy Physics - Theory · Physics 2015-06-03 C. Gonera , M. Wodzislawski