In this paper, we establish therst-order denability of sequents with consistent variable occurrence on bi-approximation semantics by means of the Sahlqvist- van Benthem algorithm. Together with the canonicity results in Suzuki (2011), this allows us to establish a Sahlqvist theorem for substructural logic. Our result is not limited to substructural logic but is also easily applicable to other lattice-based logics.
['Tomoyuki Suzuki']
A SAHLQVIST THEOREM FOR SUBSTRUCTURAL LOGIC