Bounded ranges of cardinal functions
Classical Analysis and ODEs
2025-08-19 v1 Combinatorics
Abstract
Let be a (non-empty) sequence of positive real numbers. Its achievement set is the set of all the possible sums of the elements of . The cardinal function of is the function that for every the value is equal to the number of ways is represented as a sum of elements of . In this paper we consider possible ranges of cardinal functions of sequences . We present some general constructions and several criteria that a set has to satisfy in order to be a range of a cardinal function. We put special attention to the case of sets with maximal element equal to . In this case, in particular, we obtained a full characterisation of sets that are ranges of cardinal functions of interval-filling sequences.
Keywords
Cite
@article{arxiv.2508.13016,
title = {Bounded ranges of cardinal functions},
author = {Jacek Marchwicki and Błażej Żmija},
journal= {arXiv preprint arXiv:2508.13016},
year = {2025}
}