Most simple extensions of $\mathsf{F}{\mathsf{L}}_{\mathsf{e}}$ are undecidable

Nikolaos Galatos, Gavin St. John

All known structural extensions of the substructural logic $\mathsf{F}{\mathsf{L}}_{\mathsf{e}}$, Full Lambek calculus with exchange/commutativity, (corresponding to subvarieties of commutative residuat…