English

Counting finite $O$-sequences of a given multiplicity

Commutative Algebra 2026-04-10 v2

Abstract

We study the number OdO_d of finite OO-sequences of a given multiplicity dd, with particular attention to the computation of OdO_d. We show that the sequence (Od)d(O_d)_d is sub-Fibonacci, and that if the sequence (Od/Od1)d(O_d / O_{d-1})_d converges, its limit is bounded above by the golden ratio. This analysis also produces an elementary method for computing OdO_d. In addition, we derive an iterative formula for OdO_d by exploiting a decomposition of lex-segment ideals introduced by S. Linusson in a previous work.

Keywords

Cite

@article{arxiv.2507.23438,
  title  = {Counting finite $O$-sequences of a given multiplicity},
  author = {Francesca Cioffi and Margherita Guida},
  journal= {arXiv preprint arXiv:2507.23438},
  year   = {2026}
}

Comments

Fixed some oversights in the proof of Lemma 2.2 and in the proof of Proposition 2.3; improvement of Proposition 2.5 and of Remark 2.6