Syntax n terms or 2 expressions (Terms)M,N: =X AX.M MN Lambda abstraction(x. M: anonymous"functions ntf(ntx){ return x;}→λx.x Lambda application (M n) int f (int x)i return x; y f(3) (xx)3=3Syntax •  terms or  expressions: (Terms) M, N ::= x | x. M | M N • Lambda abstraction (x.M): “anonymous” functions int f (int x) { return x; } ➔ x. x • Lambda application (M N): int f (int x) { return x; } f(3); ➔ (x. x) 3 = 3