Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.
Updated
Claim. For every prime , every with has an ordering whose partial sums are distinct, the question of Problem 475 for the sizes . This is Proposition 4.2 of S. Costa and M. A. Pellegrini, Some new results about a conjecture by Brian Alspach: the G-ADMS conjecture, their Conjecture 1.2, which asks exactly for an ordering of with distinct partial sums and which the paper attributes to Graham for prime , holds for subsets of size of cyclic groups of prime order. The proof applies Alon's Combinatorial Nullstellensatz, in the manner of Hicks, Ollis and Schmitt, to a polynomial of degree encoding an ordering of a -set with distinct partial sums; for two coefficients are computed, with greatest common divisor , so for every prime one of them is nonzero modulo (p. 6 of the arXiv version), the case being trivial. Corollaries 4.3 and 4.4 transfer the result to torsion-free abelian groups and to with all prime factors large. Read depth: claims checked for the statement in the arXiv version; the coefficient computation (Section 4.1 and the appendix) not replayed.
Covers. Every prime and every size . The sizes were known before through Alspach's conjecture (the paper's references, Theorem 2.2 of Hicks, Ollis and Schmitt for among them); the size is the paper's. Nothing about for a fixed prime.
Depends on. Nothing in this wiki: the result is the paper's own, filed on its library result page.
Acceptance. Refereed publication: Archiv der Mathematik (Basel) 115
(2020), no. 5, 479--488, published online 29 August 2020 (Crossref record; the
journal text is not held and was not compared with the arXiv version). The
site's commentary credits the sizes to this paper and its references,
but the site's label DECIDABLE leaves the problem open and settles no part of
it, so that credit is not reviewed evidence.