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We show that every sheaf on the site of smooth manifolds with values in a stable (infinity,1)-category (like spectra or chain complexes) gives rise to a differential cohomology diagram and a homotopy formula, which are common features of…

K-Theory and Homology · Mathematics 2013-11-15 Ulrich Bunke , Thomas Nikolaus , Michael Völkl

We establish direct isomorphisms between different versions of tiling cohomology. The first version is the direct limit of the cohomologies of the approximants in the Anderson-Putnam-G\"ahler complex, the second is the recently introduced…

Dynamical Systems · Mathematics 2010-07-28 Housem Boulmezaoud , Johannes Kellendonk

The intended model of the homotopy type theories used in Univalent Foundations is the infinity-category of homotopy types, also known as infinity-groupoids. The problem of higher structures is that of constructing the homotopy types needed…

Logic · Mathematics 2018-07-09 Ulrik Buchholtz

Given a diagram of schemes, we can ask if a geometric object over one of them can be built from descent data (usually objects of the same type over the various other schemes in the diagram, together with compatibility isomorphisms). Using…

Algebraic Geometry · Mathematics 2015-05-22 Daniel Schäppi

We describe a general method for algorithmic construction of G-equivariant chain homotopy equivalences from non-equivariant ones. As a consequence, we obtain an algorithm for computing equivariant (co)homology of Eilenberg-MacLane spaces…

Algebraic Topology · Mathematics 2013-04-26 Lukáš Vokřínek

Fix a scheme $X$ over a field of characteristic zero that is equipped with an action of a reductive algebraic group $G$. We give necessary and sufficient conditions for a $G$-equivariant coherent sheaf on $X$ or a bounded-above complex of…

Algebraic Geometry · Mathematics 2008-04-21 Thomas Nevins

We construct a link in the $3$-space that is not isotopic to any PL link (non-ambiently). In fact, there exist uncountably many $I$-equivalence classes of links. The paper also includes some observations on Cochran's invariants $\beta_i$.

Geometric Topology · Mathematics 2020-11-04 Sergey A. Melikhov

For discrete groups G, we introduce equivariant Nielsen invariants. They are equivariant analogs of the Nielsen number and give lower bounds for the number of fixed point orbits in the G-homotopy class of an equivariant endomorphism f:X->X.…

Algebraic Topology · Mathematics 2007-05-23 Julia Weber

In this paper we give some results on the topology of manifolds with $\infty$-Bakry-\'Emery Ricci tensor bounded below, and in particular of steady and expanding gradient Ricci solitons. To this aim we clarify and further develop the theory…

Differential Geometry · Mathematics 2018-11-15 Michele Rimoldi , Giona Veronelli

Using Gillet's technique of projective envelopes, we prove a homological descent theorem for the connective K-homology of schemes.

Algebraic Geometry · Mathematics 2020-11-13 David Anderson

We introduce two definitions of $G$-equivariant partitions of a finite $G$-set, both of which yield $G$-equivariant partition complexes. By considering suitable notions of equivariant trees, we show that $G$-equivariant partitions and…

Algebraic Topology · Mathematics 2026-02-04 Julia E. Bergner , Peter Bonventre , Maxine E. Calle , David Chan , Maru Sarazola

This article studies descent theory in the setting of Berkovich spaces. We give sufficient conditions for a given fibered category over the category of k-affinoid algebras to be a stack for the Berkovich analogue of the faithfully-flat…

Algebraic Geometry · Mathematics 2023-01-11 Mathieu Daylies

New equations governing the scale transformation behaviors of a QFT with underlying structures are derived. These equations, with their several equivalent versions, can yield some new and significant insights and results that are difficult…

High Energy Physics - Theory · Physics 2007-05-23 Jifeng Yang

We study the equivariant real structures on complex horospherical varieties, generalizing classical results known for toric varieties and flag varieties. In particular, we obtain a necessary and sufficient condition for the existence of…

Algebraic Geometry · Mathematics 2021-03-22 Lucy Moser-Jauslin , Ronan Terpereau , Mikhail Borovoi

Lurie and Gepner--Meier each define equivariant cohomology theories, namely \emph{tempered cohomology} and \emph{equivariant elliptic cohomology}, respectively, using derived algebraic geometry. We construct a natural equivalence between…

Algebraic Topology · Mathematics 2025-02-19 Jack Morgan Davies

Topological spaces - such as classifying spaces, configuration spaces and spacetimes - often admit extra temporal structure. Qualitative invariants on such directed spaces often are more informative yet more difficult to calculate than…

Algebraic Topology · Mathematics 2026-02-02 Sanjeevi Krishnan

We generalize the classical construction principles of infinite-dimensional real (and complex) Lie groups to the case of Lie groups over non-discrete topological fields. In particular, we discuss linear Lie groups, mapping groups, test…

Group Theory · Mathematics 2007-05-23 Helge Glockner

In this paper, we develop a manifestly geometric framework for equivariant manifold neural ordinary differential equations (NODEs) and use it to analyse their modelling capabilities for symmetric data. First, we consider the action of a Lie…

Machine Learning · Computer Science 2024-10-11 Emma Andersdotter , Daniel Persson , Fredrik Ohlsson

We construct a new model category presenting the homotopy theory of presheaves on "inverse EI $(\infty,1)$-categories", which contains universe objects that satisfy Voevodsky's univalence axiom. In addition to diagrams on ordinary inverse…

Algebraic Topology · Mathematics 2017-03-30 Michael Shulman

We continue our investigation of versality for parametrized families of linear retarded functional differential equations (RFDEs) projected onto finite-dimensional invariant manifolds. In this paper, we consider RFDEs equivariant with…

Dynamical Systems · Mathematics 2007-05-23 Pietro-Luciano Buono , Victor G. LeBlanc