Author: Gerald Penn Title: HPSG Design and Meet Semi-latticehood Abstract: This talk will provide an overview of meet semi-latticehood in HPSG design. Meet semi-latticehood is a structural condition on type inheritance hierarchies that ensures that the result of every unification can be determistically assigned a type. We'll take a close look at some of the justifications for eliminating this condition, the computational methods for working around it, and a new proposal for how to cope with its absence in grammar design systems.