Characterize the two-color critical multiplicity via balanced extension sizes

Characterize the two-color critical multiplicity $m_2(s)$ by proving that it belongs to the set of values obtained from pairs of integers $n_1,n_2\geq s$ satisfying $n_1+n_2=R_2(s)+2$ and $|n_1-n_2|<R(s-1,s)-(s-2)$, through the formula \[ m_2(s)\in\left\{\min_{i\in\{1,2\}}\left\{\prod_{j=0}^{s-3}\left\lceil\frac{(n_i-2)-j}{s-2}\right\rceil\right\}: n_1,n_2\geq s,\ n_1+n_2=R_2(s)+2,\ |n_1-n_2|<R(s-1,s)-(s-2)\right\}. \]

Background

The paper studies the critical multiplicity m(s1,,sk)m(s_1,\ldots,s_k), namely the number of monochromatic complete subgraphs that every coloring of the edges of the corresponding Ramsey graph must contain. Its principal upper-bound argument extends a monochromatic-clique-free coloring of KR2(s)1K_{R_2(s)-1} to a coloring of KR2(s)eK_{R_2(s)}-e, then analyzes the monochromatic copies of KsK_s created when the final edge is assigned either color.

The first conjecture proposes that an extremal coloring can be chosen so that all m2(s)m_2(s) monochromatic copies share a common edge, that the two color-specific subgraphs attain the counting bound, and that their noncommon vertices partition the graph. The displayed set-valued formula formalizes the first two structural expectations and would substantially sharpen the paper's upper bound.

References

The first two items seem reasonable, and would yield the following messy-looking conjecture (which is just \Cref{formula theorem} with one inequality replaced by an equality and another by an inclusion):

m_2(s) \in \left{\min_{i \in {1,2}\left{\prod_{j=0}{s-3}\left\lceil\frac{\big(n_i-2\big)-j}{s-2}\right\rceil\right} \enskip : \enskip \substack{n_1,n_2 \geq s, \enskip n_1+n_2 = R_2(s)+2, \ \enskip |n_1-n_2|< R\big(s-1,s\big)-(s-2)} \right}.

Bounds on the Critical Multiplicity of Ramsey Numbers with Many Colors  (2501.18869 - Christopherson et al., 31 Jan 2025) in Concluding Remarks, Conjecture 1, equations (conjbound) and (formula theorem)