Syntax ·^ terms orλ expressions: erms)M,N:=X|λx.M|MN pure n-calculus Add extra operations and data types X.(X+1) AZ.(x+2*y+2) (入.(x+1)3=3+1 ·(2.(X+2*y+z)5=x+2*y+5Syntax •  terms or  expressions: (Terms) M, N ::= x | x. M | M N • pure -calculus • Add extra operations and data types • x. (x+1) • z. (x+2*y+z) • (x. (x+1)) 3 = 3+1 • (z. (x+2*y+z)) 5 = x+2*y+5