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In this paper we study the rank of planar rigidity matrix of 4-valent graphs, both in case of generic realizations and configurations in general position, under various connectivity assumptions on the graphs. For each case considered, we…

Combinatorics · Mathematics 2012-07-16 Shisen Luo

A geometric graph in the plane is angle-monotone of width $\gamma$ if every pair of vertices is connected by an angle-monotone path of width $\gamma$, a path such that the angles of any two edges in the path differ by at most $\gamma$.…

Computational Geometry · Computer Science 2018-01-22 Anna Lubiw , Debajyoti Mondal

If $G$ is a looped graph, then its adjacency matrix represents a binary matroid $M_{A}(G)$ on $V(G)$. $M_{A}(G)$ may be obtained from the delta-matroid represented by the adjacency matrix of $G$, but $M_{A}(G)$ is less sensitive to the…

Combinatorics · Mathematics 2013-09-04 Robert Brijder , Hendrik Jan Hoogeboom , Lorenzo Traldi

In this paper, we introduce a graph matching method that can account for constraints of arbitrary order, with arbitrary potential functions. Unlike previous decomposition approaches that rely on the graph structures, we introduce a…

Computer Vision and Pattern Recognition · Computer Science 2018-02-26 D. Khuê Lê-Huu , Nikos Paragios

A d-dimensional framework is a graph and a map from its vertices to E^d. Such a framework is globally rigid if it is the only framework in E^d with the same graph and edge lengths, up to rigid motions. For which underlying graphs is a…

Metric Geometry · Mathematics 2021-10-13 Steven J. Gortler , Alexander D. Healy , Dylan P. Thurston

A bar-joint framework $(G,p)$ in the Euclidean space $\mathbb{E}^d$ is globally rigid if it is the unique realisation, up to rigid congruences, of $G$ in $\mathbb{E}^d$ with the edge lengths of $(G,p)$. Building on key results of…

Combinatorics · Mathematics 2022-06-16 Sean Dewar , John Hewetson , Anthony Nixon

Consider a graph with a rotation system, namely, for every vertex, a circular ordering of the incident edges. Given such a graph, an angle cover maps every vertex to a pair of consecutive edges in the ordering -- an angle -- such that each…

Computational Geometry · Computer Science 2022-09-23 William Evans , Ellen Gethner , Jack Spalding-Jamieson , Alexander Wolff

Graphings serve as limit objects for bounded-degree graphs. We define the ``cycle matroid'' of a graphing as a submodular setfunction, with values in [0,1], which generalizes (up to normalization) the cycle matroid of finite graphs. We…

Combinatorics · Mathematics 2023-11-08 László Lovász

We review some recent results in the generic rigidity theory of planar frameworks with forced symmetry, giving a uniform treatment to the topic. We also give new combinatorial characterizations of minimally rigid periodic frameworks with…

Geometric Topology · Mathematics 2012-03-06 Justin Malestein , Louis Theran

In mathematics and computer science, connectivity is one of the basic concepts of matroid theory: it asks for the minimum number of elements which need to be removed to disconnect the remaining nodes from each other. It is closely related…

Artificial Intelligence · Computer Science 2013-11-06 Bin Yang , William Zhu

We establish a connection between problems studied in rigidity theory and matroids arising from linear algebraic constructions like tensor products and symmetric products. A special case of this correspondence identifies the problem of…

Combinatorics · Mathematics 2026-03-04 Joshua Brakensiek , Manik Dhar , Jiyang Gao , Sivakanth Gopi , Matt Larson

We give a combinatorial characterization of generic frameworks that are minimally rigid under the additional constraint of maintaining symmetry with respect to a finite order rotation or a reflection. To establish these results we develop a…

Metric Geometry · Mathematics 2015-03-17 Justin Malestein , Louis Theran

Motivated by work in graph theory, we define the fixing number for a matroid. We give upper and lower bounds for fixing numbers for a general matroid in terms of the size and maximum orbit size (under the action of the matroid automorphism…

Combinatorics · Mathematics 2014-05-27 Gary Gordon , Jennifer McNulty , Nancy Ann Neudauer

Universality theorems (in the sense of N. Mn\"{e}v) claim that the realization space of a combinatorial object (a point configuration, a hyperplane arrangement, a convex polytope, etc.) can be arbitrarily complicated. In the paper, we prove…

Combinatorics · Mathematics 2019-10-30 Gaiane Panina

We give a combinatorial characterization of generic minimal rigidity for planar periodic frameworks. The characterization is a true analogue of the Maxwell-Laman Theorem from rigidity theory: it is stated in terms of a finite combinatorial…

Combinatorics · Mathematics 2012-10-24 Justin Malestein , Louis Theran

Necessary and sufficient conditions are obtained for the infinitesimal rigidity of braced grids in the plane with respect to non-Euclidean norms. Component rectangles of the grid may carry 0, 1 or 2 diagonal braces, and the combinatorial…

Metric Geometry · Mathematics 2020-09-24 Stephen Power

In this paper, we define the notion of rigidity for linear electrical multiports and for matroid pairs. We show the parallel between the two and study the consequences of this parallel. We present applications to testing, using purely…

Combinatorics · Mathematics 2021-03-10 H. Narayanan

A biased graph is a graph with a class of selected circles ("cycles", "circuits"), called balanced, such that no theta subgraph contains exactly two balanced circles. A biased graph $\Omega$ has two natural matroids, the frame matroid…

Combinatorics · Mathematics 2021-06-16 Rigoberto Flórez , Thomas Zaslavsky

A d-dimensional framework is an embedding of the vertices and edges of a graph in Euclidean space. A d-dimensional framework is globally rigid if every other d-dimensional framework with the same edge lengths has the same pairwise distances…

Metric Geometry · Mathematics 2010-12-30 Matthew Jacobs

It was recently proved that every planar graph is a subgraph of the strong product of a path and a graph with bounded treewidth. This paper surveys generalisations of this result for graphs on surfaces, minor-closed classes, various…

Combinatorics · Mathematics 2021-02-18 Zdeněk Dvořák , Tony Huynh , Gwenaël Joret , Chun-Hung Liu , David R. Wood