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Related papers: Extendability of $1$-decomposable complexes

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In a recent paper, we showed that every sufficiently large regular digraph G on n vertices whose degree is linear in n and which is a robust outexpander has a decomposition into edge-disjoint Hamilton cycles. The main consequence of this…

Combinatorics · Mathematics 2013-11-01 Daniela Kühn , Deryk Osthus

We prove that any finite polyhedral manifold in 3D can be continuously flattened into 2D while preserving intrinsic distances and avoiding crossings, answering a 19-year-old open problem, if we extend standard folding models to allow for…

Computational Geometry · Computer Science 2021-05-25 Zachary Abel , Erik D. Demaine , Martin L. Demaine , Jason S. Ku , Jayson Lynch , Jin-ichi Itoh , Chie Nara

We show that the complex of partial bases of the free group of rank $n$, where vertices are seen up to conjugation, is Cohen--Macaulay of dimension $n-1$. This positively answers a conjecture raised by Day and Putman. We prove our results…

Geometric Topology · Mathematics 2025-09-26 Benjamin Brück , Kevin Ivan Piterman

We study the augmented Bergman complex of a closure operator on a finite set, which interpolates between the order complex of proper flats and the independence complex of the operator. In 2020, Braden, Huh, Matherne, Proudfoot, and Wang…

Combinatorics · Mathematics 2022-04-13 R. Amzi Jeffs

A simplicial complex $\Delta$ is a virtually Cohen-Macaulay simplicial complex if its associated Stanley-Reisner ring $S$ has a virtual resolution, as defined by Berkesch, Erman, and Smith, of length ${\rm codim}(S)$. We provide a…

Commutative Algebra · Mathematics 2024-12-10 Jay Yang , Adam Van Tuyl

For a positive integer $k$ and a non-negative integer $t$ a class of simplicial complexes, to be denoted by $k$-${\rm CM}_t$, is introduced. This class generalizes two notions for simplicial complexes: being $k$-Cohen-Macaulay and…

Commutative Algebra · Mathematics 2009-12-22 Hassan Haghighi , Rahim Zaare-Nahandi , Siamak Yassemi

For a graph $G$ on $[n]$, the $k$-cut complex $\Delta_k(G)$ has facets $[n]\setminus T$, where $T$ ranges over the disconnected $k$-vertex induced subgraphs of $G$. Bayer, Denker, Jeli\'c Milutinovi\'c, Sundaram, and Xue proved that the…

Combinatorics · Mathematics 2026-05-28 Yutong Zhang , Yaoran Yang

This paper considers the question of how to succinctly approximate a multidimensional convex body by a polytope. Given a convex body $K$ of unit diameter in Euclidean $d$-dimensional space (where $d$ is a constant) and an error parameter…

Computational Geometry · Computer Science 2022-12-09 Rahul Arya , Sunil Arya , Guilherme D. da Fonseca , David M. Mount

We show how a filtration of Delaunay complexes can be used to approximate the persistence diagram of the distance to a point set in $R^d$. Whereas the full Delaunay complex can be used to compute this persistence diagram exactly, it may…

Computational Geometry · Computer Science 2020-12-04 Donald R. Sheehy

We produce examples of generalized complex structures on manifolds by generalizing results from symplectic and complex geometry. We produce generalized complex structures on symplectic fibrations over a generalized complex base. We study in…

Differential Geometry · Mathematics 2007-05-23 Gil R. Cavalcanti

Vertical decomposition is a widely used general technique for decomposing the cells of arrangements of semi-algebraic sets in $d$-space into constant-complexity subcells. In this paper, we settle in the affirmative a few long-standing open…

Computational Geometry · Computer Science 2023-11-06 Pankaj K. Agarwal , Esther Ezra , Micha Sharir

A dissection of a convex d-polytope is a partition of the polytope into d-simplices whose vertices are among the vertices of the polytope. Triangulations are dissections that have the additional property that the set of all its simplices…

Combinatorics · Mathematics 2013-04-30 Jesús A. De Loera , Francisco Santos , Fumihiko Takeuchi

In a previous article [JHEP 1111 (2011) 072; arXiv:1108.4965] we have developed a Lorentzian version of the Quantum Regge Calculus in which the significant differences between simplices in Lorentzian signature and Euclidean signature are…

General Relativity and Quantum Cosmology · Physics 2012-01-13 Kyle Tate , Matt Visser

Decomposable ordered structures were introduced in \cite{OnSt} to develop a general framework to study `finite-dimensional' totally ordered structures. This paper continues this work to include decomposable structures on which a ordered…

Logic · Mathematics 2014-02-27 Eliana Barriga , Alf Onshuus , Charles Steinhorn

We prove a formula for the polar degree of projective hypersurfaces in terms of the Milnor data of the singularities, extending to 1-dimensional singularities the Dimca-Papadima result for isolated singularities. We discuss the…

Algebraic Geometry · Mathematics 2022-05-18 Dirk Siersma , Mihai Tibăr

While faces of a polytope form a well structured lattice, in which faces of each possible dimension are present, this is not true for general compact convex sets. We address the question of what dimensional patterns are possible for the…

Metric Geometry · Mathematics 2017-03-23 Vera Roshchina , Tian Sang , David Yost

An orientation preserving diffeomorphism over a surface embedded in a 4-manifold is called extendable, if this diffeomorphism is a restriction of an orientation preserving diffeomorphism on this 4-manifold. In this paper, we investigate…

Geometric Topology · Mathematics 2014-10-01 Susumu Hirose

A two-dimensional simplicial complex is called $d$-{\em regular} if every edge of it is contained in exactly $d$ distinct triangles. It is called $\epsilon$-expanding if its up-down two-dimensional random walk has a normalized maximal…

Combinatorics · Mathematics 2020-04-27 Eyal Karni , Tali Kaufman

We extend a theorem by Juh\'asz and Szentmikl\'ossy to notions related to pseudocompactness. We also allow the case when one of the cardinals under consideration is singular. We give an application to the study of decomposable ultrafilters:…

General Topology · Mathematics 2013-05-23 Paolo Lipparini

Motivated by potential applications in network theory, engineering and computer science, we study $r$-ample simplicial complexes. These complexes can be viewed as finite approximations to the Rado complex which has a remarkable property of…

Algebraic Topology · Mathematics 2023-09-14 Chaim Even-Zohar , Michael Farber , Lewis Mead