Resolvable-derived-STS conjecture for SQS(n), n congruent to 4 modulo 6

From papers

Let an SQS(n)(n) be a Steiner quadruple system on nn points, and let a derived STS be the Steiner triple system obtained by fixing a point of the SQS and deleting that point from every block containing it. A Steiner triple system is resolvable when its blocks can be partitioned into parallel classes.

Resolvable-derived-STS conjecture. If

n4mod6,n \equiv 4 \bmod 6,

then there is an SQS(n)(n) such that all its derived STS are resolvable.

This conjecture is used to obtain q0(3,4,n)=n/2q'_0(3,4,n)=n/2. The source reports it as known for n=10n=10, for several families admitting 2-resolvable SQSs, and for sufficiently large nn with n4mod12n\equiv4\bmod12, but not in general.

Progress summary

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Sources & referencesView supporting material

Primary source

Minjia Shi, Yuhong Xia and Denis S. Krotov, “A family of diameter perfect constant-weight codes from Steiner systems”, arXiv:2212.00048 (2023).

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