English

Semi-magic dihedral squares

Combinatorics 2026-02-26 v2

Abstract

Let Γ\Gamma be a group of order n2n^2 and SMSΓ(n)=(ai,j)n×nSMS_{\Gamma}(n)=(a_{i,j})_{n\times n} be an n×nn\times n array whose entries are all distinct elements of Γ\Gamma. If there exists an element μΓ\mu\in\Gamma such that for every row ii, there exists an ordering of elements such that ai,j1ai,j2ai,jn1ai,jn=μ a_{i,j_1} a_{i,j_2} \dots a_{i,j_{n-1}} a_{i,j_n} = \mu and for every column jj there exists an ordering of elements such that ai1,jai2,jaim1,jaim,j=μ, a_{i_1,j} a_{i_2,j} \dots a_{i_{m-1},j} a_{i_m,j} = \mu, then SMSΓ(n)SMS_{\Gamma}(n) is called a \emph{Γ\Gamma-semi-magic square of side nn} and μ\mu is called a \emph{magic constant}. We provide a complete characterization of semi-magic squares of side nn whose entries belong to a dihedral group DkD_k. Moreover, we show that in our constructions a single semi-magic square may admit two distinct magic constants, depending on the order in which the products are computed.

Cite

@article{arxiv.2602.20774,
  title  = {Semi-magic dihedral squares},
  author = {Sylwia Cichacz and Dalibor Froncek},
  journal= {arXiv preprint arXiv:2602.20774},
  year   = {2026}
}
R2 v1 2026-07-01T10:49:42.587Z