Task: Text Categorization
Input (English): De Bruijn invented an alternative syntax for use in this system, and Sinot created director strings in order to find the complexity cost of beta reduction in this system. Rosser and one formulator of this system found a paradox proving the untyped version of this system to be inconsistent as a basis for logic, while Rosser and the other creator of this system showed that this system possesses confluence. The funarg problem can arise when implementing this system in stack-based languages, since such an implementation requires treating functions as first-class objects. Containing "abstractions" and "applications," this system was shown to be Turing-complete. Implemented in functional programming languages such as Haskell and Lisp, for 10 points, name this formal system for representing functions, developed by Stephen Kleene and Alonzo Church and named for a Greek symbol.
Output (English): Science