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Bondage Number


The bondage number b(G) of a finite simple graph G with at least one graph edge is the minimum number of graph edges whose deletion increases its domination number (Fink et al. 1990). Writing E(G) for the edge set and gamma(G) for the domination number,

 b(G)=min{|F|:F subset= E(G),gamma(G-F)>gamma(G)},

where G-F is obtained by edge deletion of every graph edge in F, retaining all graph vertices.

For the truncated octahedral graph T, Srivastava (2026) proved that gamma(T)=8 and b(T)=5. Since T is planar and cubic, this refutes the planar bondage conjecture, which proposed the bound b(G)<=Delta(G)+1, where Delta(G) is the maximum vertex degree. Srivastava (2026) reports using OpenAI Codex for search-code development and independent-check design.


See also

Domination Number, Edge Deletion, Planar Bondage Conjecture

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References

Fink, J. F.; Jacobson, M. S.; Kinch, L. F.; and Roberts, J. "The Bondage Number of a Graph." Disc. Math. 86, 47-57, 1990. https://doi.org/10.1016/0012-365X(90)90348-L.Srivastava, P. R. "The Truncated Octahedral Graph Has Bondage Number Five." 2 Sep 2026. https://arxiv.org/abs/2609.02477.

Cite this as:

Weisstein, Eric W. "Bondage Number." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/BondageNumber.html

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