Scott-product compatibility for countable meet-continuous complete lattices

Determine whether every countable meet-continuous complete lattice L satisfies the Scott-product identity σ(L × L) = σ(L) × σ(L).

Background

The paper proves the Scott-product identity for countable frames, which are meet-continuous because frames satisfy the stronger distributivity law, and for Artinian meet-continuous dcpos. It also proves that equality of the Scott topology on L × L with the ordinary product of the Scott topologies implies sobriety of the Scott space of a complete lattice.

The unresolved question asks whether countability together with meet continuity, without finite distributivity or Artinianity, is sufficient for the product identity in the complete-lattice setting. An affirmative answer would imply sobriety of the Scott space by Proposition 2.2.

References

Let $L$ be a countable meet-continuous complete lattice. Must

\sigma(L\times L)=\sigma(L)\times\sigma(L)?

— Scott topologies on products of countable complete Heyting algebras  (2609.18032 - Xu, 16 Sep 2026) in Question 2.1, Section 6 (Further questions)