Latin hypercubes realizing integer partitions
Diane Donovan, Tara Kemp, James Lefevre
TL;DR
This work extends Fuchs' 2-realization problem to $m$-ary quasigroups by studying $m$-realizations via latin hypercubes and develops a general toolkit based on outline rectangles and boxes. It provides constructive methods to build latin cubes from latin squares, inflations, and prolongations, and proves that a $2$-RP always yields a $3$-RP, with two key necessary (but not sufficient) conditions guiding the existence of $3$-realizations. The paper delivers detailed results for partitions with at most two distinct parts, establishing sharp bounds such as $a\le 2b$ for $\mathrm{3-RP}(a^1b^2)$ and $a\le (n-1)b$ in higher-part scenarios, while highlighting limits via outline-box non-extendability. Finally, it generalizes to $m$-dimensional hypercubes, showing how realizations can be propagated across dimensions and establishing congruence-based growth, with explicit high-dimensional examples demonstrating richer realizability phenomena beyond the binary case.
Abstract
For an integer partition $h_1 + \dots + h_n = N$, a 2-realization of this partition is a latin square of order $N$ with disjoint subsquares of orders $h_1,\dots,h_n$. The existence of 2-realizations is a partially solved problem posed by Fuchs. In this paper, we extend Fuchs' problem to $m$-ary quasigroups, or, equivalently, latin hypercubes. We construct latin cubes for some partitions with at most two distinct parts and highlight how the new problem is related to the original.
