The eventual structure of non-terminal residue classes for Stirling-number valuations

From papers

Let S(n,k)S(n,k) denote the number of partitions of an nn-element set into exactly kk nonempty subsets, and let v2v_2 denote the 22-adic valuation. For fixed kNk\in\mathbb{N}, consider the residue classes

Cm,j(k)={2mi+j:iN and 2mi+jk}.C_{m,j}^{(k)}=\{2^m i+j:i\in\mathbb{N}\text{ and }2^m i+j\geq k\}.

A class is non-terminal if v2(S(n,k))v_2(S(n,k)) is not constant on it, and terminal otherwise; the parameter mm is the level of the class. The eventual non-terminal-class conjecture. For every fixed kNk\in\mathbb{N}, there exist a level m0(k)m_0(k) and an integer μ(k)\mu(k) such that, for every mm0(k)m\geq m_0(k), the number of non-terminal classes of level mm is μ(k)\mu(k), independently of mm. Moreover, for each mm0(k)m\geq m_0(k), every one of these μ(k)\mu(k) non-terminal classes splits into one terminal subclass and one non-terminal subclass, with the latter generating the set of classes at the next level.

The conjecture proposes an eventual stable branching pattern for the 22-adic valuations of Stirling numbers when kk is fixed. The source gives the explicit valuations for 1k41\leq k\leq4 but does not provide a resolution of the general assertion.

Progress summary

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

Sources & referencesView supporting material

Primary source

Shubham, “The p-adic valuation of the general degree-2 and degree-3 polynomial in 2 variables”, arXiv:2407.07103 (2024).

Additional references

2 papers in this index state this conjecture (2022–2024). The statement above is taken from the most recent of them; the others are arXiv:2203.02197.

Solutions 0

No solutions have been posted yet.