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The triangulations of a regular convex polygon are enumerated according to the number of diagonals parallel to a fixed edge. The enumeration uses the Shapiro convolution identity, as well as an interpretation of this identity in terms of…

组合数学 · 数学 2012-08-21 Alon Regev

Maximal $(k+1)$-crossing-free graphs on a planar point set in convex position, that is, $k$-triangulations, have received attention in recent literature, with motivation coming from several interpretations of them. We introduce a new way of…

组合数学 · 数学 2012-06-14 Vincent Pilaud , Francisco Santos

A triangulation of a connected closed surface is called weakly regular if the action of its automorphism group on its vertices is transitive. A triangulation of a connected closed surface is called degree-regular if each of its vertices…

几何拓扑 · 数学 2007-05-23 Basudeb Datta , Ashish Kumar Upadhyay

We revisit here a fundamental result on planar triangulations, namely that the flip distance between two triangulations is upper-bounded by the number of proper intersections between their straight-segment edges. We provide a complete and…

计算复杂性 · 计算机科学 2021-06-29 Thomas Dagès , Alfred M. Bruckstein

We study the maximal number of triangulations that a planar set of $n$ points can have, and show that it is at most $30^n$. This new bound is achieved by a careful optimization of the charging scheme of Sharir and Welzl (2006), which has…

离散数学 · 计算机科学 2010-01-03 Micha Sharir , Adam Sheffer

We study flip graphs of triangulations whose maximum vertex degree is bounded by a constant $k$. In particular, we consider triangulations of sets of $n$ points in convex position in the plane and prove that their flip graph is connected if…

A {\em $1-$vertex triangulation} of an oriented compact surface $S$ of genus $g$ is an embedded graph $T\subset S$ with a unique vertex such that all connected components of $S\setminus T$ are triangles (adjacent to exactly 3 edges of $T$).…

组合数学 · 数学 2007-05-23 Roland Bacher , Alina Vdovina

Convex hexagons that can tile the plane have been classified into three types. For the generic cases (not necessarily convex) of the three types and two other special cases, we classify tilings of the plane under the assumption that all…

组合数学 · 数学 2024-05-09 Xinlu Yu , Erxiao Wang , Min Yan

We describe some theoretical results on triangulations of surfaces and we develop a theory on roots, decompositions and genus-surfaces. We apply this theory to describe an algorithm to list all triangulations of closed surfaces with at most…

组合数学 · 数学 2019-01-30 Gennaro Amendola

We show that 4-connected plane triangulations can be redrawn such that edges are represented by straight segments and the vertices are covered by a set of at most $\sqrt{2n}$ lines each of them horizontal or vertical. The same holds for all…

组合数学 · 数学 2019-08-15 Stefan Felsner

If all but two vertices of a triangulated sphere have degrees divisible by $k$, then the exceptional vertices are not adjacent. This theorem is proved for $k=2$ with the help of the coloring monodromy. For $k = 3, 4, 5$ colorings by the…

组合数学 · 数学 2015-11-23 Ivan Izmestiev

We show that every sufficiently large plane triangulation has a large collection of nested cycles that either are pairwise disjoint, or pairwise intersect in exactly one vertex, or pairwise intersect in exactly two vertices. We apply this…

组合数学 · 数学 2019-04-29 Cesar Hernandez-Velez , Gelasio Salazar , Robin Thomas

We show that a general plane curve of degree at least 4 is uniquely determined by the full set of its bitangent lines. This problem has an elementary solution for degree at least 5, and the paper is almost entirely devoted to curves of…

代数几何 · 数学 2007-05-23 Lucia Caporaso , Edoardo Sernesi

The number of triangulations of a planar n point set is known to be $c^n$, where the base $c$ lies between $2.43$ and $30.$ The fastest known algorithm for counting triangulations of a planar n point set runs in $O^*(2^n)$ time. The fastest…

计算几何 · 计算机科学 2014-11-21 Marek Karpinski , Andrzej Lingas , Dzmitry Sledneu

We show that every simple planar near-triangulation with minimum degree at least three contains two disjoint total dominating sets. The class includes all simple planar triangulations other than the triangle. This affirms a conjecture of…

组合数学 · 数学 2022-05-16 P. Francis , Abraham M. Illickan , Lijo M. Jose , Deepak Rajendraprasad

We introduce series-triangular graph embeddings and show how to partition point sets with them. This result is then used to improve the upper bound on the number of Steiner points needed to obtain compatible triangulations of point sets.…

计算几何 · 计算机科学 2007-05-23 Jeff Danciger , Satyan L. Devadoss , Don Sheehy

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…

几何拓扑 · 数学 2007-05-23 Basudeb Datta

For every positive integer $n$, we find a complete classification for planar graphs according to the collection of numbers of common neighbours for every $n$-tuple of distinct vertices. Our results expand the literature on planar graphical…

组合数学 · 数学 2025-11-25 Riccardo W. Maffucci

In this work we consider triangulations of point sets in the Euclidean plane, i.e., maximal straight-line crossing-free graphs on a finite set of points. Given a triangulation of a point set, an edge flip is the operation of removing one…

计算几何 · 计算机科学 2015-05-13 Alexander Pilz

We determine the maximum number of edges that a planar graph can have as a function of its maximum degree and matching number.

组合数学 · 数学 2022-07-08 Lars Jaffke , Paloma T. Lima