The "glue" approach to semantic composition in Lexical-Functional Grammar uses linear logic to assemble meanings from syntactic analyses (Dalrymple et al., 1993). It has been compurationally feasible in practice (Dalrymple et al., 1997b). Yet deduction in linear logic is known to be intractable. Even the propositional tensor fragment is NP complete(Kanovich, 1992). In this paper, we investigate what has made the glue approach computationally feasible and show how to exploit that to efficiently deduce underspecified representations. .