The Larch Project develops aids for formal specifICations. Each Larch specifICation has two components: an interface containing predICates written in the LIL ({Larch Interface Language}) designed for the target language and a ' trait' containing assertions about the predICates written in LSL, the Larch Shared Language common to all. ["The Larch Family of SpecifICation Languages", J. Guttag et al, IEEE Trans Soft Eng 2(5):24-365 (Sep 1985)].