Cavenagh–Hämäläinen–Lefevre–Stones completion conjecture for partial multi-Latin squares

From papers

Let rr and λ\lambda be positive integers. A simple partial λ\lambda-Latin square of order rr is an r×rr\times r array whose cells contain multisets of at most λ\lambda symbols, with each symbol occurring at most λ\lambda times in each row and column, and with no repeated symbol in any cell. A simple λ\lambda-Latin square of order nn is an n×nn\times n array in which each cell contains a multiset of λ\lambda symbols, each symbol occurs at most λ\lambda times in each row and column, and no cell contains repeated symbols.

Cavenagh–Hämäläinen–Lefevre–Stones' conjecture. For each r,λNr,\lambda\in\mathbb N, there exists an integer n(r,λ)n(r,\lambda) such that, for every nn(r,λ)n\geq n(r,\lambda), every simple partial r×rr\times r λ\lambda-Latin square can be extended to a simple n×nn\times n λ\lambda-Latin square.

The conjecture asks for a uniform sufficiently large order guaranteeing completion of every simple partial multi-Latin square. The paper states that it confirms this conjecture, while the supplied status for this candidate is open; the status should therefore be checked against the paper's final completion result.

Progress summary

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Sources & referencesView supporting material

Primary source

Amin Bahmanian, “Ryser's Theorem for Simple Multi-Latin Rectangle”, arXiv:2509.11471 (2025).

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