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Related papers: Balanced subdivisions and flips on surfaces

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Congruent polygons are congruent in angles as well as in edge lengths. We concentrate on the angle aspect, and investigate how tilings of the sphere by congruent pentagons can be determined by the angle information only. We also investigate…

Combinatorics · Mathematics 2026-04-29 Robert Barish , Hoi Ping Luk , Min Yan

A key result in computational 3-manifold topology is that any two triangulations of the same 3-manifold are connected by a finite sequence of bistellar flips, also known as Pachner moves. One limitation of this result is that little is…

Geometric Topology · Mathematics 2025-10-10 Benjamin A. Burton , Alexander He

We develop a theory of simple pentagonal subdivision of quadrilateral tilings, on orientable as well as non-orientable surfaces. Then we apply the theory to answer questions related to pentagonal tilings of surfaces, especially those…

Combinatorics · Mathematics 2019-08-23 Min Yan

We characterise which simplicial surfaces can be folded onto a triangle. We define a notion of folding that incorporates the non-intersection-properties of real materials. All of the surfaces foldable onto a triangle admit a…

Combinatorics · Mathematics 2019-04-30 Markus Baumeister

Boolean operations of geometric models is an essential issue in computational geometry. In this paper, we develop a simple and robust approach to perform Boolean operations on closed and open triangulated surfaces. Our method mainly has two…

Computational Geometry · Computer Science 2023-07-19 Gang Mei , John C. Tipper

Tight triangulated manifolds are generalisations of neighborly triangulations of closed surfaces and are interesting objects in Combinatorial Topology. Tight triangulated manifolds are conjectured to be minimal. Except few, all the known…

Geometric Topology · Mathematics 2015-06-02 Basudeb Datta

We prove two results about transforming any convex polyhedron, modeled as a linkage L of its edges. First, if we subdivide each edge of L in half, then L can be continuously flattened into a plane. Second, if L is equilateral and we again…

Computational Geometry · Computer Science 2024-12-20 Erik D. Demaine , Martin L. Demaine , Markus Hecher , Rebecca Lin , Victor H. Luo , Chie Nara

In this paper we give a classification of tilings of the sphere by congruent quadrilaterals with exactly two equal edges. The tilings are the earth map tilings, $(p,q)$-earth map tilings and their flip modifications, and quadrilateral…

Combinatorics · Mathematics 2021-09-06 Ho Man Cheung , Hoi Ping Luk

A classical result by Pachner states that two $d$-dimensional combinatorial manifolds with boundary are PL homeomorphic if and only they can be connected by a sequence of shellings and inverse shellings. We prove that for balanced, i.e.,…

Combinatorics · Mathematics 2018-04-18 Martina Juhnke-Kubitzke , Lorenzo Venturello

In this survey article, we are interested on minimal triangulations of closed pl manifolds. We present a brief survey on the works done in last 25 years on the following: (i) Finding the minimal number of vertices required to triangulate a…

Geometric Topology · Mathematics 2007-05-23 Basudeb Datta

Delaunay flip is an elegant, simple tool to convert a triangulation of a point set to its Delaunay triangulation. The technique has been researched extensively for full dimensional triangulations of point sets. However, an important case of…

Computational Geometry · Computer Science 2007-12-13 Siu-Wing Cheng , Tamal K. Dey

We completely classify edge-to-edge tilings of the sphere by congruent quadrilaterals. As part of the classification, we also present a modern version of the classification of edge-to-edge tilings of the sphere by congruent triangles.…

Combinatorics · Mathematics 2024-02-09 Ho Man Cheung , Hoi Ping Luk , Min Yan

We consider the problem of finding an inductive construction, based on vertex splitting, of triangulated spheres with a fixed number of additional edges (braces). We show that for any positive integer $b$ there is such an inductive…

Combinatorics · Mathematics 2021-07-09 James Cruickshank , Eleftherios Kastis , Derek Kitson , Bernd Schulze

A small triangulation of the sphere product can be found in lower dimensions by computer search and is known in few other cases: Klee and Novik constructed a centrally symmetric triangulation of $\mathbb{S}^i\times \mathbb{S}^{d-i-1}$ with…

Combinatorics · Mathematics 2019-10-18 Alexander Wang , Hailun Zheng

A combinatorial tiling of the sphere is naturally given by an embedded graph. We study the case that each tile has exactly five edges, with the ultimate goal of classifying combinatorial tilings of the sphere by geometrically congruent…

Combinatorics · Mathematics 2014-05-13 Min Yan

Trivalent $2$-stratifolds are a generalization of $2$-manifolds in that there are disjoint simple closed curves where three sheets meet. We develop operations on their associated labeled graphs that will effectively construct from a single…

Geometric Topology · Mathematics 2018-05-17 J. C. Gómez-Larrañaga , F. González-Acuña , Wolfgang Heil , Y. A. Hernández-Esparza

We show that $O(n^2)$ exchanging flips suffice to transform any edge-labelled pointed pseudo-triangulation into any other with the same set of labels. By using insertion, deletion and exchanging flips, we can transform any edge-labelled…

Computational Geometry · Computer Science 2015-12-07 Prosenjit Bose , Sander Verdonschot

We consider domino tilings of three-dimensional cubiculated manifolds with or without boundary, including subsets of Euclidean space and three-dimensional tori. In particular, we are interested in the connected components of the space of…

Combinatorics · Mathematics 2021-06-17 Juliana Freire , Caroline J. Klivans , Pedro H. Milet , Nicolau C. Saldanha

The edge-to-edge tilings of the sphere by congruent quadrilaterals of Type $a^2bc$ are classified as $3$ classes: a sequence of two-parameter families of $2$-layer earth map tilings with $2n$ $(n\ge3)$ tiles, a one-parameter family of…

Combinatorics · Mathematics 2022-07-26 Yixi Liao , Pinren Qian , Erxiao Wang , Yingyun Xu

Every simple quadrangulation of the sphere is generated by a graph called a pseudo-double wheel with two local expansions (Brinkmann et al. "Generation of simple quadrangulations of the sphere." Discrete Math., Vol. 305, No. 1-3, pp. 33-54,…

Metric Geometry · Mathematics 2012-10-08 Yohji Akama