Functional Programming, Haskell, Computer Science, Lambda Calculus, Algorithms.
applied to an argument, the occurrence of its variable is replaced by an argument, wherever that argument is, even outside itself. Here is an example: λt. t a b ((λa. λb. λc. c) 1 2 3) --------------------------------- lambda application λt. t 1 b ((λb. λc. c) 2 3) ---------------------------