Two Complete Axiom Systems for the Extended Language of Regular Expressions
IEEE Transactions on Computers · 1968
—Two consistent and complete formal systems for the algebraic transformation of regular expressions involving intersections and complements are given. Both systems are extensions of the system F1presented in Salomaa [5]. As a result, a method of eliminating intersections and complements from regular expressions is obtained. This solves a problem proposed by Eggan.