Stembridge characterizes regular crystals associated with a simply-laced GCM in terms of local graph-theoretic quantities. We give a similar axiomatization for $B_2$ regular crystals and thus for regular crystals of finite GCM except $G_2$ and affine GCM except $A^{(1)}_1, G^{(1)}_2, A^{(2)}_2, D^{(3)}_4$.
As we will explain in detail the previous studies, finding a set of local axioms that characterizes $B_2$ regular crystals has been an open problem.

The venue is Maskawa Building for Education and Research Room 507