This is the lambda-lists package by Alan Jeffrey, for doing lists and
lambda calculus via expandable macros (a.k.a. in TeX's mouth).

For historical reasons, the code is available in a file named
lambda.sty; it runs under both plain TeX and LaTeX.  It is unrelated to
the lambda format that is part of Omega.

The documentation is in lambda-lists.{tex,pdf}.  It was originally
published as an article in TUGboat, vol.11, no.2, pp.237-245.
http://tug.org/TUGboat.

The entire package is released under the LPPL.  It consists of this
README, lambda.sty, lambda-lists.tex, and the derived file
lambda-lists.pdf.

Web page with contact info: http://ect.bell-labs.com/who/ajeffrey.