7 Program semantics and infinite regular terms

The communication by Gilles Kahn, Jean Vuillemin and myself at the second International Colloquium on Automata, Languages and Programming, held in Saarbrücken in 1974 is in French in the proceedings, and has not been published as a journal article. However, Todd Veldhuizen wrote in 2002 an English translation that is reproduced in the next chapter. À propos Chapter 8 It was quite a surprise for me to receive a message from Todd Veldhuizen saying that he had translated from French a 30-year-old conference paper presented at the second International Colloquium on Automata, Languages and Programming, held in Saarbrücken in 1974, of which I am coauthor with G. Kahn and J. Vuillemin. He did that work because he felt the paper was “seminal”. First of all I would like to thank him for this work. The publication of his translation in a volume dedicated to the memory of Gilles Kahn is a testimony of the gratitude of Jean Vuillemin and myself to him, and the recognition of an important scientific contribution of Gilles among many others. In this overview, I indicate a few research directions that can be traced back to that communication. I give only a few related references, this overview is not a thorough bibliographical review of related articles. In the late 1960s, D. Scott constructed the first model of lambdacalculus, and his construction has been a corner stone for the theory of semantic domains and for denotational semantics [10,12]. Formal semantics of programming languages was beginning during these years. From Semantics to Computer Science Essays in Honour of Gilles Khan, eds Yves Bertot, Gérard Huet, Jean-Jacques Lévy and Gordon Plotkin. Published by Cambridge University Press. c © Cambridge University Press 2009.