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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 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

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

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…

In structural rigidity, one studies frameworks of bars and joints in Euclidean space. Such a framework is an articulated structure consisting of rigid bars, joined together at joints around which the bars may rotate. In this paper, we will…

Combinatorics · Mathematics 2024-08-28 Joannes Vermant , Klara Stokes

Some aspects of a mathematical theory of rigidity and flexibility are developed for general infinite frameworks and two main results are obtained. In the first sufficient conditions, of a uniform local nature, are obtained for the existence…

Functional Analysis · Mathematics 2008-11-19 J. C. Owen , S. C. 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

The minimal infinitesimal rigidity of bar-joint frameworks in the non-Euclidean spaces (R^2, ||.||_q) are characterised in terms of (2,2)-tight graphs. Specifically, a generically placed bar-joint framework (G,p) in the plane is minimally…

Metric Geometry · Mathematics 2017-05-17 Derek Kitson , Stephen Power

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

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

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

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

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

We develop a combinatorial rigidity theory for symmetric bar-joint frameworks in a general finite dimensional normed space. In the case of rotational symmetry, matroidal Maxwell-type sparsity counts are identified for a large class of…

Metric Geometry · Mathematics 2020-04-17 Derek Kitson , Anthony Nixon , Bernd Schulze

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

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

A rigidity theory is developed for the Euclidean and non-Euclidean placements of countably infinite simple graphs in R^d with respect to the classical l^p norms, for d>1 and 1<p<\infty. Generalisations are obtained for the Laman and…

Metric Geometry · Mathematics 2013-10-08 D. Kitson , S. C. Power

Combinatorial characterisations are obtained of symmetric and anti-symmetric infinitesimal rigidity for two-dimensional frameworks with reflectional symmetry in the case of norms where the unit ball is a quadrilateral and where the…

Metric Geometry · Mathematics 2017-09-27 Derek Kitson , Bernd Schulze

A (bar-and-joint) framework is a set of points in a normed space with a set of fixed distance constraints between them. Determining whether a framework is locally rigid - i.e. whether every other suitably close framework with the same…

Metric Geometry · Mathematics 2024-01-18 Sean Dewar

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
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