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We show that a generic framework $(G,p)$ on the cylinder is globally rigid if and only if $G$ is a complete graph on at most four vertices or $G$ is both redundantly rigid and $2$-connected. To prove the theorem we also derive a new…

Combinatorics · Mathematics 2018-10-16 Bill Jackson , Anthony Nixon

A rigidity theory is developed for bar-joint frameworks in $\mathbb{R}^{d+1}$ whose vertices are constrained to lie on concentric $d$-spheres with independently variable radii. In particular, combinatorial characterisations are established…

Metric Geometry · Mathematics 2017-02-14 Anthony Nixon , Bernd Schulze , Shin-ichi Tanigawa , Walter Whiteley

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 deformations of the vertices arise from…

Combinatorics · Mathematics 2023-12-18 Anthony Nixon , Bernd Schulze , Joseph Wall

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

We extend our generic rigidity theory for periodic frameworks in the plane to frameworks with a broader class of crystallographic symmetry. Along the way we introduce a new class of combinatorial matroids and associated linear…

Geometric Topology · Mathematics 2015-03-19 Justin Malestein , Louis Theran

For plane frameworks with reflection or rotational symmetries, where the group action is not necessarily free on the vertex set, we introduce a phase-symmetric orbit rigidity matrix for each irreducible representation of the group. We then…

Combinatorics · Mathematics 2024-07-19 Alison La Porta , Bernd Schulze

In this paper we consider the effect of symmetry on the rigidity of bar-joint frameworks, spherical frameworks and point-hyperplane frameworks in $\mathbb{R}^d$. In particular we show that, under forced or incidental symmetry, infinitesimal…

Combinatorics · Mathematics 2019-06-07 Katie Clinch , Anthony Nixon , Bernd Schulze , Walter Whiteley

We give a combinatorial characterization of generic minimally rigid reflection frameworks. The main new idea is to study a pair of direction networks on the same graph such that one admits faithful realizations and the other has only…

Geometric Topology · Mathematics 2012-03-13 Justin Malestein , Louis Theran

A fundamental theorem of Laman characterises when a bar-joint framework realised generically in the Euclidean plane admits a non-trivial continuous deformation of its vertices. This has recently been extended in two ways. Firstly to…

Metric Geometry · Mathematics 2015-07-31 Anthony Nixon , Bernd Schulze

A rigidity theory is developed for frameworks in a metric space with two types of distance constraints. Mixed sparsity graph characterisations are obtained for the infinitesimal and continuous rigidity of completely regular bar-joint…

Metric Geometry · Mathematics 2019-08-26 Anthony Nixon , Stephen Power

A theorem of Laman gives a combinatorial characterisation of the graphs that admit a realisation as a minimally rigid generic bar-joint framework in $\bR^2$. A more general theory is developed for frameworks in $\bR^3$ whose vertices are…

Combinatorics · Mathematics 2012-10-05 A. Nixon , J. C. Owen , S. C. Power

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

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 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

Fekete, Jord\'an and Kaszanitzky [4] characterised the graphs which can be realised as 2-dimensional, infinitesimally rigid, bar-joint frameworks in which two given vertices are coincident. We formulate a conjecture which would extend their…

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

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

In 2005, Bob Connelly showed that a generic framework in $\bR^d$ is globally rigid if it has a stress matrix of maximum possible rank, and that this sufficient condition for generic global rigidity is preserved by the 1-extension operation.…

Metric Geometry · Mathematics 2015-06-22 Bill Jackson , Anthony Nixon

A natural problem in combinatorial rigidity theory concerns the determination of the rigidity or flexibility of bar-joint frameworks in $\mathbb{R}^d$ that admit some non-trivial symmetry. When $d=2$ there is a large literature on this…

Combinatorics · Mathematics 2025-09-30 Sean Dewar , Georg Grasegger , Eleftherios Kastis , Anthony Nixon

We consider the rigidity and global rigidity of bar-joint frameworks in Euclidean $d$-space under additional dilation constraints in specified coordinate directions. In this setting we obtain a complete characterisation of generic rigidity.…

Combinatorics · Mathematics 2024-02-23 Sean Dewar , Anthony Nixon , Andrew Sainsbury

A longstanding problem in rigidity theory is to characterize the graphs which are minimally generically rigid in 3-space. The results of Cauchy, Dehn, and Alexandrov give one important class: the triangulated convex spheres, but there is an…

Metric Geometry · Mathematics 2010-07-07 Wendy Finbow-Singh , Walter Whiteley
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