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Starting from any proper action of any locally compact quantum group on any discrete quantum space, we show that its equivariant representation theory yields a concrete unitary 2-category of finite type Hilbert bimodules over the discrete…

Operator Algebras · Mathematics 2025-08-27 Lukas Rollier

We consider the problem of efficiently computing a discrete Morse complex on simplicial complexes of arbitrary dimension and very large size. Based on a common graph-based formalism, we analyze existing data structures for simplicial…

Computational Geometry · Computer Science 2018-11-13 Ulderico Fugacci , Federico Iuricich , Leila De Floriani

For a finite simplicial complex K and a CW-pair (X,A), there is an associated CW-complex Z_K(X,A), known as a polyhedral product. We apply discrete Morse theory to a particular CW-structure on the n-sphere moment-angle complexes Z_K(D^{n},…

Combinatorics · Mathematics 2012-12-21 Vladimir Grujic , Volkmar Welker

We introduce and analyze parallelizable algorithms to compress and accurately reconstruct finite simplicial complexes that have non-trivial automorphisms. The compressed data -- called a complex of groups -- amounts to a functor from (the…

Group Theory · Mathematics 2020-04-21 Lisa Carbone , Vidit Nanda , Yusra Naqvi

We develop a discrete Morse theory for open simplicial complexes $K=X\setminus T$ where $X$ is a simplicial complex and $T$ a subcomplex of $X$. A discrete Morse function $f$ on $K$ gives rise to a discrete Morse function on the order…

Algebraic Topology · Mathematics 2026-02-23 Kevin P. Knudson , Nicholas A. Scoville

In this paper, we develop methods for calculating equivariant homology from equivariant Morse functions on a closed manifold with the action of a finite group. We show how to alter $G$-equivariant Morse functions to a stable one, where the…

Geometric Topology · Mathematics 2025-02-04 Erkao Bao , Tyler Lawson

In this paper, we study Forman's discrete Morse theory in the context of weighted homology. We develop weighted versions of classical theorems in discrete Morse theory. A key difference in the weighted case is that simplicial collapses do…

Algebraic Topology · Mathematics 2020-02-05 Chengyuan Wu , Shiquan Ren , Jie Wu , Kelin Xia

Discrete Morse theory emerged as an essential tool for computational geometry and topology. Its core structures are discrete gradient fields, defined as acyclic matchings on a complex $C$, from which topological and geometrical informations…

Geometric Topology · Mathematics 2018-01-31 Joao Paixao , Joao Lagoas , Thomas Lewiner , Tiago Novello

We introduce a perfect discrete Morse function on the moduli space of a polygonal linkage. The ingredients of the construction are: (1) the cell structure on the moduli space, and (2) the discrete Morse theory approach, which allows to…

Algebraic Topology · Mathematics 2016-01-26 Gaiane Panina , Alena Zhukova

Our main result is a local-to-global principle for Morse quasigeodesics, maps and actions. As an application of our techniques we show algorithmic recognizability of Morse actions and construct Morse ``Schottky subgroups'' of higher rank…

Differential Geometry · Mathematics 2025-08-20 Michael Kapovich , Bernhard Leeb , Joan Porti

We show how to construct homology bases for certain CW complexes in terms of discrete Morse theory and cellular homology. We apply this technique to study certain subcomplexes of the half cube polytope studied in previous works. This…

Geometric Topology · Mathematics 2014-10-01 R. M. Green , Jacob T. Harper

Forman introduced discrete Morse theory as a tool for studying CW complexes by essentially collapsing them onto smaller, simpler-to-understand complexes of critical cells in [Fo]. Chari reformulated discrete Morse theory for regular cell…

Combinatorics · Mathematics 2018-08-24 Patricia Hersh

Discrete Morse theory, a cell complex-analog to smooth Morse theory, has been developed over the past few decades since its original formulation by Robin Forman in 1998. In particular, discrete gradient vector fields on simplicial complexes…

Combinatorics · Mathematics 2022-07-05 Ivan Contreras , Andrew R. Tawfeek

To any finite simplicial complex X, we associate a natural filtration starting from Chari and Joswig's discrete Morse complex and abutting to the matching complex of X. This construction leads to the definition of several homology theories,…

Combinatorics · Mathematics 2022-02-11 Daniele Celoria , Naya Yerolemou

A $2$-matching complex is a simplicial complex which captures the relationship between $2$-matchings of a graph. In this paper, we will use discrete Morse Theory and the Matching Tree Algorithm to prove homotopical results. We will consider…

Combinatorics · Mathematics 2021-02-01 Julianne Vega

In this paper, we determine the homotopy type of the Morse complex of certain collections of simplicial complexes by studying dominating vertices or strong collapses. We show that if $K$ contains two leaves that share a common vertex, then…

Algebraic Topology · Mathematics 2021-07-19 Connor Donovan , Maxwell Lin , Nicholas A. Scoville

In the case of smooth manifolds, we use Forman's discrete Morse theory to realize combinatorially any Thom-Smale complex coming from a smooth Morse function by a couple triangulation-discrete Morse function. As an application, we prove that…

Geometric Topology · Mathematics 2008-12-18 Etienne Gallais

We construct a 2-category version of tom Dieck's equivariant fundamental groupoid for representable orbifolds and show that the discrete fundamental groupoid is Morita invariant; hence an orbifold invariant for representable orbifolds.

Algebraic Topology · Mathematics 2019-08-06 Dorette Pronk , Laura Scull

We develop functoriality for Morse theory, namely, to a pair of Morse-Smale systems and a generic smooth map between the underlying manifolds we associate a chain map between the corresponding Morse complexes, which descends to the correct…

Differential Geometry · Mathematics 2009-10-12 Avraham Aizenbud , Frol Zapolsky

We extend the combinatorial Morse complex construction to the arbitrary free chain complexes, and give a short, self-contained, and elementary proof of the quasi-isomorphism between the original chain complex and its Morse complex. Even…

Discrete Mathematics · Computer Science 2007-05-23 Dmitry N. Kozlov