A system for reducing the operational notation of logic,

mathematics or a functional language to a sequence of

modifications to the input data structure. First introduced

in the 1920's by Schoenfinkel. Re-introduced independently

by Haskell Curry in the late 1920's (who quickly learned of

Schoenfinkel's work after he had the idea). Curry is really

responsible for most of the development, at least up until

work with Feys in 1958.