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A linearly constrained framework in $\mathbb{R}^d$ is a point configuration together with a system of constraints which fixes the distances between some pairs of points and additionally restricts some of the points to lie in given affine…

Combinatorics · Mathematics 2022-12-09 Hakan Guler , Bill Jackson , Anthony Nixon

A bar-joint framework $(G,p)$ in Euclidean $d$-space is rigid if the only edge-length-preserving continuous motions arise from isometries of $\mathbb{R}^d$. In the generic case, rigidity is determined by the generic $d$-dimensional rigidity…

Combinatorics · Mathematics 2025-06-30 Rebecca Monks , Anthony Nixon

We explore the rigidity of generic frameworks in 3-dimensions whose underlying graph is close to being planar. Specifically we consider apex graphs, edge-apex graphs and their variants and prove independence results in the generic…

Combinatorics · Mathematics 2024-02-28 Sean Dewar , Georg Grasegger , Eleftherios Kastis , Anthony Nixon , Brigitte Servatius

A 2-dimensional point-line framework is a collection of points and lines in the plane which are linked by pairwise constraints that fix some angles between pairs of lines and also some point-line and point-point distances. It is rigid if…

Metric Geometry · Mathematics 2016-05-26 Bill Jackson , J. C. Owen

We develop a rigidity theory for bar-joint frameworks in Euclidean $d$-space in which specified classes of edges are allowed to change length in a coordinated fashion that requires differences of lengths to be preserved within each class.…

Metric Geometry · Mathematics 2022-06-14 Bernd Schulze , Hattie Serocold , Louis Theran

A bar-joint framework $(G,p)$ is the combination of a graph $G$ and a map $p$ assigning positions, in some space, to the vertices of $G$. The framework is rigid if every edge-length-preserving continuous motion of the vertices arises from…

Combinatorics · Mathematics 2021-12-21 Sean Dewar , John Hewetson , Anthony Nixon

This paper studies the properties of two kinds of matroids: (a) algebraic matroids and (b) finite and infinite matroids whose ground set have some canonical symmetry, for example row and column symmetry and transposition symmetry. For (a)…

Combinatorics · Mathematics 2013-12-16 Franz J. Király , Zvi Rosen , Louis Theran

A two-dimensional direction-length framework $(G,p)$ consists of a multigraph $G=(V;D,L)$ whose edge set is formed of "direction" edges $D$ and "length" edges $L$, and a realisation $p$ of this graph in the plane. The edges of the framework…

Combinatorics · Mathematics 2016-08-31 Katie Clinch

As an extension of a classical tree-partition problem, we consider decompositions of graphs into edge-disjoint (rooted-)trees with an additional matroid constraint. Specifically, suppose we are given a graph $G=(V,E)$, a multiset…

Combinatorics · Mathematics 2011-09-06 Naoki Katoh , Shin-ichi Tanigawa

We introduce the parametric matroid one-interdiction problem. Given a matroid, each element of its ground set is associated with a weight that depends linearly on a real parameter from a given parameter interval. The goal is to find, for…

Combinatorics · Mathematics 2024-08-15 Nils Hausbrandt , Oliver Bachtler , Stefan Ruzika , Luca E. Schäfer

A $d$-dimensional (bar-and-joint) framework $(G,p)$ consists of a graph $G=(V,E)$ and a realisation $p:V\to \mathbb{R}^d$. It is rigid if every continuous motion of the vertices which preserves the lengths of the edges is induced by an…

History and Overview · Mathematics 2025-08-19 James Cruickshank , Bill Jackson , Tibor Jordán , Shin-ichi Tanigawa

For a finite point set $E\subset \mathbb{R}^d$ and a connected graph $G$ on $k+1$ vertices, we define a $G$-framework to be a collection of $k + 1$ points in E such that the distance between a pair of points is specified if the…

Combinatorics · Mathematics 2018-05-22 A. Iosevich , J. Passant

A linearly constrained framework in $\mathbb{R}^d$ is a bar-joint framework where, in addition, vertices with loops are constrained to lie in given affine subspaces. In the generic case, when each vertex is incident to sufficiently many…

Combinatorics · Mathematics 2026-05-19 Zakir Deniz , Hakan Guler , Anthony Nixon

This paper presents an angle-based approach for distributed formation shape stabilization of multi-agent systems in the plane. We develop an angle rigidity theory to study whether a planar framework can be determined by angles between…

Systems and Control · Computer Science 2019-03-05 Gangshan Jing , Guofeng Zhang , Heung Wing Joseph Lee , Long Wang

Combinatorial rigidity theory seeks to describe the rigidity or flexibility of bar-joint frameworks in R^d in terms of the structure of the underlying graph G. The goal of this article is to broaden the foundations of combinatorial rigidity…

Combinatorics · Mathematics 2011-10-05 Mike Develin , Jeremy L. Martin , Victor Reiner

A bar-joint framework $(G,p)$ is the combination of a finite simple graph $G=(V,E)$ and a placement $p:V\rightarrow \mathbb{R}^d$. The framework is rigid if the only edge-length preserving continuous motions of the vertices arise from…

Combinatorics · Mathematics 2023-12-20 Anthony Nixon , Bernd Schulze , Joseph Wall

A number of recent papers have studied when symmetry causes frameworks on a graph to become infinitesimally flexible, or stressed, and when it has no impact. A number of other recent papers have studied special classes of frameworks on…

Metric Geometry · Mathematics 2010-06-07 Bernd Schulze , Walter Whiteley

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 has two natural matroids, the frame matroid and the lift…

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

A mixed graph is a graph with some directed edges and some undirected edges. We introduce the notion of mixed matroids as a generalization of mixed graphs. A mixed matroid can be viewed as an oriented matroid in which the signs over a fixed…

Combinatorics · Mathematics 2007-05-23 J. Orestes Cerdeira , Raul Cordovil

We consider the global rigidity problem for bar-joint frameworks where each vertex is constrained to lie on a particular line in $\mathbb R^d$. In our setting we allow multiple vertices to be constrained to the same line. Under a mild…

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