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. See combinATor. (1995-01-05)