Clique restrictions in minimally globally rigid graphs
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Can an edge-minimal generically globally rigid graph in Rᵈ with at least d+3 vertices contain K_(d+2)? The conjectured exclusion retains K_(d+2) itself as the exceptional minimally globally rigid graph containing that clique.
Why it matters and what counts as progress
Why it matters: It asks how global rigidity constrains dense local subgraphs when every edge is essential.
What counts as progress: Prove the forbidden-clique structure for every dimension and allowed graph size, retaining the exceptional complete graph.
How the problem developed
- 1992 · Necessary conditions [1]
Bruce Hendrickson Showed that generic global rigidity requires (d+1)-connectivity and redundant rigidity, outside the small complete-graph cases.
- 2005 · Sufficient condition [1]
Robert Connelly Established a stress-matrix sufficient condition for generic global rigidity and conjectured it was also necessary.
- 2010 · Characterization [1]
Steven J. Gortler, Alexander D. Healy and Dylan P. Thurston Proved Connelly’s conjecture, characterizing generic global rigidity through a stress matrix of rank n−d−1.
- 30 Apr 2026 · Clique restriction [2]
Frédéric Portier Reported that an edge-minimal generically globally rigid graph in Rᵈ with at least d+3 vertices contains no K_(d+2), except the clique itself.
AI contribution
Cliques in minimally globally rigid graphs
Portier proves that an edge-minimal generically globally rigid graph in Rᵈ with at least d+3 vertices contains no K_(d+2) subgraph. Equivalently, the only minimally globally rigid graph containing that clique is K_(d+2) itself.
Sources
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Publication dates and editorial changes.
ChatGPT-found proof excludes large cliques in minimally rigid graphs