Back to Search Start Over

Weak sequenceability in cyclic groups.

Authors :
Costa, Simone
Della Fiore, Stefano
Source :
Journal of Combinatorial Designs. Dec2022, Vol. 30 Issue 12, p735-751. 17p.
Publication Year :
2022

Abstract

A subset A $A$ of an abelian group G $G$ is sequenceable if there is an ordering (a1,...,ak) $({a}_{1},\ldots ,{a}_{k})$ of its elements such that the partial sums (s0,s1,...,sk) $({s}_{0},{s}_{1},\ldots ,{s}_{k})$, given by s0=0 ${s}_{0}=0$ and si=∑j=1iaj ${s}_{i}={\sum }_{j=1}^{i}{a}_{j}$ for 1≤i≤k $1\le i\le k$, are distinct, with the possible exception that we may have sk=s0=0 ${s}_{k}={s}_{0}=0$. In the literature there are several conjectures and questions concerning the sequenceability of subsets of abelian groups, which have been combined and summarized by Alspach and Liversidge into the conjecture that if a subset of an abelian group does not contain 0 then it is sequenceable. If the elements of a sequenceable set A $A$ do not sum to 0 then there exists a simple path P $P$ in the Cayley graph Cay[G:±A] $Cay[G:\pm A]$ such that Δ(P)=±A ${\rm{\Delta }}(P)=\pm A$. In this paper, inspired by this graph–theoretical interpretation, we propose a weakening of this conjecture. Here, under the above assumptions, we want to find an ordering whose partial sums define a walk W $W$ of girth bigger than t $t$ (for a given t<k $t\lt k$) and such that Δ(W)=±A ${\rm{\Delta }}(W)=\pm A$. This is possible given that the partial sums si ${s}_{i}$ and sj ${s}_{j}$ are different whenever i $i$ and j $j$ are distinct and ∣i−j∣≤t $| i-j| \le t$. In this case, we say that the set A $A$ is t $t$‐weakly sequenceable. The main result here presented is that any subset A $A$ of Zp⧹{0} ${{\mathbb{Z}}}_{p}\setminus \{0\}$ is t $t$‐weakly sequenceable whenever t<7 $t\lt 7$ or when A $A$ does not contain pairs of type {x,−x} $\{x,-x\}$ and t<8 $t\lt 8$. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
10638539
Volume :
30
Issue :
12
Database :
Academic Search Index
Journal :
Journal of Combinatorial Designs
Publication Type :
Academic Journal
Accession number :
159630333
Full Text :
https://doi.org/10.1002/jcd.21862