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Rigidity Matrix


The d-dimensional rigidity matrix M(G) of a graph G with vertex count n, edge count m in the variables v_i=(x_1,...,x_d) is the m×(dn) matrix with rows indexed by the edges and columns indexed by the variables in v_i, in which the entry in row e and columns v is

 {v_i-w   if e-vw is incident with v; 0   if e is not incident with v.
(1)

The rigidity matrix of a framework (G,p) is the matrix M(G,p) obtained from M(G) by replacing v by p(v) for all vertices.


See also

Incidence Matrix, Rigid Graph

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References

Connelly, R. and Guest, S. D. Frameworks, Tensegrities and Symmetry. Cambridge, England: Cambridge University Press, 2022.Grasegger, G. "RigiComp--a Mathematica Package for Computational Rigidity of Graphs." Dec. 19, 2022. https://zenodo.org/record/7457820#.Y7V1Ay-B30o.Grasegger, G. "Minimal Counterexamples to Hendrickson's Conjecture on Globally Rigid Graphs." Examples and Counterexamples 3, 100106, 2023.Graver, J.; Servatius, B.; and Servatius, H. Combinatorial Rigidity. Providence, RI: Amer. Math. Soc., 1993.Roth, B. "Rigid and Flexible Frameworks." Amer. Math. Monthly 88, 6-21, 1981.Sitharam, M.; St. John, A.; and Sidman, J. (Eds.). Handbook of Geometric Constraint Systems Principles. Boca Raton, FL: CRC Press, 2018.

Cite this as:

Weisstein, Eric W. "Rigidity Matrix." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/RigidityMatrix.html

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