Magic squares of squares over a finite field
Document Type
Conference Proceeding
Publication Date
1-1-2021
Abstract
A magic square M over an integral domain D is a 3×3 matrix with entries from D such that the elements from each row, column, and diagonal add to the same sum. If all the entries in M are perfect squares in D, we call M a magic square of squares over D. In 1984, Martin LaBar raised an open question: “Is there a magic square of squares over the ring Z of the integers which has all the nine entries distinct?” We approach to answering a similar question when D is a finite field. We claim that for any odd prime p, a magic square over Zp can only hold an odd number of distinct entries. Corresponding to LaBar’s question, we show that there are infinitely many prime numbers p such that, over Zp, magic squares of squares with nine distinct elements exist. In addition, if p ≡ 1 (mod 120), there exist magic squares of squares over Zp that have exactly 3, 5, 7, or 9 distinct entries respectively. We construct magic squares of squares using triples of consecutive quadratic residues derived from twin primes.
Publication Title
Contemporary Mathematics
First Page Number
111
Last Page Number
122
DOI
10.1090/conm/773/15536
Recommended Citation
Hengeveld, Stewart; Labruna, Giancarlo; and Li, Aihua, "Magic squares of squares over a finite field" (2021). Kean Publications. 1060.
https://digitalcommons.kean.edu/keanpublications/1060