Large-column existence conjecture

Prove that $(r\times c,v)$-near triple arrays exist for every $r\geq 3$, $c\geq r(r-1)$, and $v\geq c$.

Background

The paper proves that near triple arrays with three rows exist whenever c6=3(31)c\geq 6=3(3-1) and vcv\geq c. It also proves a non-existence result for each fixed r4r\geq 4 at c=r(r1)1c=r(r-1)-1 and v=c+2v=c+2, showing that the threshold in the conjecture is motivated by a sharp obstruction.

The conjecture proposes that the bound cr(r1)c\geq r(r-1) is sufficient for existence for all numbers of symbols at least equal to the number of columns.

References

We therefore propose the following conjecture.

\begin{conjecture} $(r \times c, v)$-near triple arrays exist for any $c \geq r(r - 1)$ and $v \geq c$. \end{conjecture}

Near Triple Arrays  (2503.07166 - Gordeev et al., 10 Mar 2025) in Conjecture in Section 7, Concluding remarks (Section \ref{sec:concl})