Agrawal's ordering conjecture for extremal unordered triple arrays

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Let UU be an (r×c,r+c−1)(r\times c,r+c-1)-unordered triple array, let ee denote its mixed intersection parameter, and assume e>2e>2. An ordered triple array TT has underlying unordered triple array UTU_T.

Agrawal's ordering conjecture. For any (r×c,r+c−1)(r\times c,r+c-1)-unordered triple array UU with e>2e>2, there is an (r×c,r+c−1)(r\times c,r+c-1)-triple array TT with UT=UU_T=U.

This strengthens Agrawal's existence conjecture by requiring every eligible unordered triple array to be orderable. The paper states that it remains open, with computational evidence and special cases discussed later.

References

Primary source

Alexey Gordeev and Lars-Daniel Öhman, “Resolvable Triple Arrays”, arXiv:2512.08681 (2026).

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