This article will demonstrate basic arithmetic operations  comparison, addition, subtraction, multiplication, and division  on nonnegative and negative integer numbers. Both the integers and the operations on them are represented as terms in the pure untyped lambdacalculus. The only building blocks are identifiers, abstractions and applications. No constants or deltarules are used. Reductions follow only the familiar betasubstitution and etarules.
Implementing substraction in the LC can be a bit challenging. Natrually, the problem is related to the method used to represent numbers as lambdacalculus terms. This rather subtle issue is explored, and demonstrated.
Posted to LC by Ehud Lamm on 6/5/01; 4:06:24 AM

