Mollusc: A General Proof-Development Shell for Sequent-Based Logics

This article describes an interactive proof development shell, Mollusc Richards 93], which can be used to construct and edit proofs in sequent-based logics. Conceptually, Mollusc may be thought of as a logic-independent successor to Oyster Bundy et al 90]. However, where Oyster was tied to a variant of Martin-LL of type theory, Mollusc can be used with any sequent-based logic for which a suitable deenition is provided. Although developed in a research environment, Mollusc should also be suitable for use in classroom exercises. In addition to proof editing facilities, Mollusc supports the deenition of new logics, includes a proof-planner interface, and provides for automated proof construction through a tactic language and interpreter.