Ore-type toughness conjecture for hamiltonicity

Let GG be a tt-tough graph on n3n\ge 3 vertices. Define

σ2(G)=min{dG(u)+dG(v):u,vV(G), u and v are nonadjacent}\sigma_2(G)=\min\{d_G(u)+d_G(v):u,v\in V(G),\ u\text{ and }v\text{ are nonadjacent}\}

for noncomplete GG, and set σ2(G)=\sigma_2(G)=\infty when GG is complete. A graph is hamiltonian if it contains a hamiltonian cycle.

Ore-type toughness conjecture. If

σ2(G)>2nt+12,\sigma_2(G)>\frac{2n}{t+1}-2,

then GG is hamiltonian.

The statement strengthens the paper's proved Ore-type condition by removing the additive tt term. It is presented as a stronger statement that might be true and remains open.

Sources & referencesView supporting material

Primary source

Songling Shan, “An Ore-type condition for hamiltonicity in tough graphs”, arXiv:2103.05146 (2022).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.