Type B product conjecture for middle orders

Let BnB_n be the type BB finite Coxeter group, with n3n\geq3, and let JJ be a maximal parabolic subgroup. A middle order is a distributive lattice that refines the weak order and is coarsened by the Bruhat order. Type B product conjecture. Every middle order on BnB_n can be obtained as the product of a middle order on WJW_J and a distributive sorting order on JW{}^JW.

This would give a recursive description of all middle orders in type BB from maximal parabolic data; it is stated conjecturally and remains open.

Sources & referencesView supporting material

Primary source

Ludovic Schwob, “Middle orders: all distributive lattices between weak and Bruhat”, arXiv:2606.12129 (2026).

Progress summary

Never refreshed

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

Solutions 0

No solutions have been posted yet.