A non-recursive algorithm computing set expressions

This paper concerns set expressions satisfying some constraints. Although algorithms processing expressions (for every kind) have been proposed in compilers, almost all of them use stacks and recursions, and adopt complicated parsing techniques. However, the simplification of set expressions can be done easily by its special characteristics. In this paper, we propose linear, nonrecursive, and thus efficient algorithms simplifying set expressions. The method can be well used in proposition calculus.