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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

A result due in its various parts to Hendrickson, Connelly, and Jackson and Jord\'an, provides a purely combinatorial characterisation of global rigidity for generic bar-joint frameworks in $\mathbb{R}^2$. The analogous conditions are known…

Metric Geometry · Mathematics 2013-06-12 Bill Jackson , Thomas McCourt , Anthony Nixon

For a complex projective space the inertia group, the homotopy inertia group and the concordance inertia group are isomorphic. In complex dimension 4n+1, these groups are related to computations in stable cohomotopy. Using stable homotopy…

Algebraic Topology · Mathematics 2018-03-16 Samik Basu , Ramesh Kasilingam

We present a rigorous study of framework rigidity in general finite dimensional normed spaces from the perspective of Lie group actions on smooth manifolds. As an application, we prove an extension of Asimow and Roth's 1978/9 result…

Metric Geometry · Mathematics 2019-09-24 Sean Dewar

This article is concerned with the rigidity properties of geometric realizations of incidence geometries of rank two as points and lines in the Euclidean plane; we care about the distance being preserved among collinear points. We discuss…

Combinatorics · Mathematics 2022-04-28 Signe Lundqvist , Klara Stokes , Lars-Daniel Öhman

A framework, which is a (possibly infinite) graph with a realization of its vertices in the plane, is called flexible if it can be continuously deformed while preserving the edge lengths. We focus on flexibility of frameworks in which…

Combinatorics · Mathematics 2024-04-26 Georg Grasegger , Jan Legerský

A framework (a straight-line embedding of a graph into a normed space allowing edges to cross) is globally rigid if any other framework with the same edge lengths with respect to the chosen norm is an isometric copy. We investigate global…

Metric Geometry · Mathematics 2025-04-04 Sean Dewar

This paper deals with certain results on the number of smooth structures on quaternionic projective spaces, obtained through the computation of inertia group and its analogues, which in turn are computed using techniques from stable…

Geometric Topology · Mathematics 2023-02-08 Samik Basu , Ramesh Kasilingam

This work considers the problem of estimating the unscaled relative positions of a multi-robot team in a common reference frame from bearing-only measurements. Each robot has access to a relative bearing measurement taken from the local…

Optimization and Control · Mathematics 2015-03-03 Daniel Zelazo , Antonio Franchi , Paolo Robuffo Giordano

We introduce and study asymptotically rigid mapping class groups of certain infinite graphs. We determine their finiteness properties and show that these depend on the number of ends of the underlying graph. In a special case where the…

Geometric Topology · Mathematics 2025-09-01 Thomas Hill , Sanghoon Kwak , Brian Udall , Jeremy West

In this paper a special group of bijective maps of a normed plane, called the group of general rotations, is introduced; it contains the isometry group as a subgroup. The concept of general rotations leads to the notion of flexible motions…

Metric Geometry · Mathematics 2016-05-30 Vitor Balestro , Ákos G. Horváth , Horst Martini

We construct infinite periodic versions of the stress matrix and establish sufficient conditions for periodic tensegrity frameworks to be globally rigid in $\mathbb{R}^d$ in the cases when the lattice is either fixed, fully flexible, or…

Metric Geometry · Mathematics 2025-10-23 Sean Dewar , Bernd Schulze , Shin-ichi Tanigawa , Louis Theran

A rigidity theory is developed for bar-joint frameworks in linear matrix spaces endowed with a unitarily invariant norm. Analogues of Maxwell's counting criteria are obtained and minimally rigid matrix frameworks are shown to belong to the…

Metric Geometry · Mathematics 2017-09-27 Derek Kitson , Rupert H. Levene

The combinatorial characterization of generic rigidity for bar-joint frameworks in dimensions $d \ge 3$ has been a long-standing open problem in discrete geometry. While the two-dimensional case was resolved in 1927 by Pollaczek-Geiringer…

Combinatorics · Mathematics 2026-04-21 Alexander Heaton

A bar-joint framework $(G,p)$ in a (non-Euclidean) real normed plane $X$ is the combination of a finite, simple graph $G$ and a placement $p$ of the vertices in $X$. A framework $(G,p)$ is globally rigid in $X$ if every other framework…

Metric Geometry · Mathematics 2024-01-18 Sean Dewar , Anthony Nixon

We characterise finite and infinitesimal rigidity for bar-joint frameworks in R^d with respect to polyhedral norms (i.e. norms with closed unit ball P a convex d-dimensional polytope). Infinitesimal and continuous rigidity are shown to be…

Metric Geometry · Mathematics 2014-01-08 D. Kitson

Let P be a locally finite disk pattern on the complex plane C whose combinatorics are described by the one-skeleton G of a triangulation of the open topological disk and whose dihedral angles are equal to a function \Theta:E\to [0,\pi/2] on…

Complex Variables · Mathematics 2016-09-07 Zheng-Xu He

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

We characterise rigid graphs for cylindrical normed spaces $Z=X\oplus_\infty \mathbb{R}$ where $X$ is a finite dimensional real normed linear space and $Z$ is endowed with the product norm. In particular, we obtain purely combinatorial…

Metric Geometry · Mathematics 2023-05-16 Sean Dewar , Derek Kitson

We consider the space of all configurations of finitely many (potentially nested) circles in the plane. We prove that this space is aspherical, and compute the fundamental group of each of its connected components. It turns out these…

Algebraic Topology · Mathematics 2026-01-14 Justin Curry , Ryan C. Gelnett , Matthew C. B. Zaremsky