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Related papers: Equivariant Trees and Partition Complexes

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We look for partition theorems for large subtrees for suitable uncountable trees and colourings. We concentrate on sub-trees of $^{\kappa \ge} 2$ expanded by a well ordering of each level. Unlike earlier works, we do not ask the embedding…

Logic · Mathematics 2026-01-06 Saharon Shelah

Let T be a tree with an action of a finitely generated group G. Given a suitable equivalence relation on the set of edge stabilizers of T (such as commensurability, co-elementarity in a relatively hyperbolic group, or commutation in a…

Group Theory · Mathematics 2016-01-20 Vincent Guirardel , Gilbert Levitt

For stacked simplicial complexes, (special subclasses of such are: trees, triangulations of polygons, stacked polytopes), we give an explicit bijection between partitions of facets (for trees: edges), and partitions of vertices into…

Combinatorics · Mathematics 2024-01-17 Gunnar Fløystad

We give an algebraic description of several modules and algebras related to the vector partition function, and we prove that they can be realized as the equivariant K-theory of some manifolds that have a nice combinatorial description. We…

K-Theory and Homology · Mathematics 2015-09-30 Francesco Cavazzani , Luca Moci

We introduce and compare two approaches to equivariant homotopy theory in a topological or ordinary Quillen model category. For the topological model category of spaces, we generalize Piacenza's result that the categories of topological…

Algebraic Topology · Mathematics 2017-03-06 Marc Stephan

We set up operadic foundations for equivariant iterated loop space theory. We start by building up from a discussion of the approximation theorem and recognition principle for V-fold loop G-spaces to several avatars of a recognition…

Algebraic Topology · Mathematics 2018-03-16 Bertrand Guillou , J. P. May

We use sheaf theory and the six operations to define and study the (equivariant) homology of stacks. The construction makes sense in the algebraic, complex-analytic, or even topological categories.

Algebraic Topology · Mathematics 2025-06-06 Adeel A. Khan

We extend the Cisinski-Moerdijk-Weiss theory of $\infty$-operads to the equivariant setting to obtain a notion of $G$-$\infty$-operads that encode "equivariant operads with norm maps" up to homotopy. At the root of this work is the…

Algebraic Topology · Mathematics 2018-05-02 Luis Alexandre Pereira

Let G be a discrete group. We give methods to compute for a generalized (co-)homology theory its values on the Borel construction (EG x X)/G of a proper G-CW-complex X satisfying certain finiteness conditions. In particular we give formulas…

K-Theory and Homology · Mathematics 2012-01-24 Michael Joachim , Wolfgang Lueck

We present in the context of Gorenstein homological algebra the notion of a "G-Gorenstein complex" as the counterpart of the classical notion of a Gorenstein complex. In particular, we investigate equivalences between the category of…

Commutative Algebra · Mathematics 2014-08-27 Maryam Akhavin , Eero Hyry

Building on structure observed in equivariant homotopy theory, we define an equivariant generalization of a symmetric monoidal category: a $G$-symmetric monoidal category. These record not only the symmetric monoidal products but also…

Algebraic Topology · Mathematics 2016-10-12 Michael A. Hill , Michael J. Hopkins

We extend the concept of a Hubbard tree, well established and useful in the theory of polynomial dynamics, to the dynamics of transcendental entire functions. We show that Hubbard trees in the strict traditional sense, as invariant compact…

Dynamical Systems · Mathematics 2025-09-01 David Pfrang , Michael Rothgang , Dierk Schleicher

We define and study equivariant periodic cyclic homology for locally compact groups. This can be viewed as a noncommutative generalization of equivariant de Rham cohomology. Although the construction resembles the Cuntz-Quillen approach to…

K-Theory and Homology · Mathematics 2007-05-23 Christian Voigt

We show that the poset of non-trivial partitions of 1,2,...,n has a fundamental homology class with coefficients in a Lie superalgebra. Homological duality then rapidly yields a range of known results concerning the integral representations…

Category Theory · Mathematics 2014-10-01 Alan Robinson

We present a new definition of non-ambiguous trees (NATs) as labelled binary trees. We thus get a differential equation whose solution can be described combinatorially. This yield a new formula for the number of NATs. We also obtain…

Given a topological group G, its orbit category Orb_G has the transitive G-spaces G/H as objects and the G-equivariant maps between them as morphisms. A well known theorem of Elmendorf then states that the category of G-spaces and the…

Algebraic Topology · Mathematics 2007-05-23 Andre Henriques , David Gepner

We develop a quasisymmetric analogue of the combinatorial theory of Schubert polynomials and the associated divided difference operators. Our counterparts are "forest polynomials", and a new family of linear operators, whose theory of…

Combinatorics · Mathematics 2026-02-03 Philippe Nadeau , Hunter Spink , Vasu Tewari

For any finite group G with a finite G-set X and a modular tensor category C we construct a part of the algebraic structure of an associated G-equivariant monoidal category: For any group element g in G we exhibit the module category…

Quantum Algebra · Mathematics 2010-06-22 Till Barmeier

We study the realization problem of finite groups as the group of homotopy classes of self-homotopy equivalences of finite spaces. Let $G$ be a finite group. Using an infinite family of pairwise non weakly homotopic asymmetric spaces we…

Algebraic Topology · Mathematics 2025-02-27 Juan Felipe Celis-Rojas

We present a new definition of non-ambiguous trees (NATs) as labelled binary trees. We thus get a differential equation whose solution can be described combinatorially. This yields a new formula for the number of NATs. We also obtain…

Discrete Mathematics · Computer Science 2021-03-26 Bérénice Delcroix-Oger , Florent Hivert , Patxi Laborde-Zubieta , Jean-Christophe Aval , Adrien Boussicault