Equality of T2 and the pseudo-regularization of SQ

Determine whether the variety T2 of commutative idempotent groupoids defined by the identity x (y · yz) = (xy · y) z coincides with the pseudo-regularization \overline{SQ} of the variety SQ of Steiner quasigroups (commutative idempotent groupoids satisfying xy · y = x).

Background

The variety SQ consists of Steiner quasigroups, i.e., commutative idempotent groupoids satisfying xy * y = x. Its regularization SQ is strictly contained in the pseudo-regularization \overline{SQ}, which is defined by identities (P1)–(P4) with the pseudopartition operation t(x,y) = xy * y.

Prior work shows that the variety T2, consisting of commutative idempotent groupoids satisfying x (y * yz) = (xy * y) z, is contained in \overline{SQ} and is different from SQ. It is unknown whether \overline{SQ} equals T2.

References

However we do not know if the varieties \mathcal{T}_2 and \overline{SQ} coincide, though we think it is not likely.

Semilattice sums of algebras and Mal'tsev products of varieties  (2603.29747 - Bergman et al., 31 Mar 2026) in Section 'Examples and counterexamples', Example [Steiner quasigroups]