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We describe an implementation of the Display Logic calculus for relation algebra as an Isabelle theory. Our implementation is the rst mechanisation of any display calculus, but also provides a useful interactive proof assistant for relation algebra. The inference rules of Display Logic are coded directly as Isabelle theorems, thereby guaranteeing the(More)
We use a deep embedding of the display calculus for relation algebras δRA in the logical framework Isabelle/HOL to formalise a new, machine-checked, proof of strong normalisation and cut-elimination for δRA which does not use measures on the size of derivations. Our formalisation generalises easily to other display calculi and can serve as a basis for(More)
We compare several methods of implementing the display (sequent) calculus RA for relation algebra in the logical frameworks Isabelle and Twelf. We aim for an implementation enabling us to for-malise within the logical framework proof-theoretic results such as the cut-elimination theorem for RA and any associated increase in proof length. We discuss issues(More)
Full Intuitionistic Linear Logic (FILL) is multiplicative intuitionistic linear logic extended with par. Its proof theory has been notoriously difficult to get right, and existing sequent calculi all involve inference rules with complex annotations to guarantee soundness and cut-elimination. We give a simple and annotation-free display calculus for FILL(More)