The Optimal Approach to Recursive Programs The classical fixed poin t approach toward recursive programs suggests choosing the "least defined fixed poin t" as the most appropriate solution to a recursive program. A new approach is described which in troduction an " optimal fixed point," which, in contrast to the least defined fixed poin t, embodies the maximal amount of valuable information embedded in the program. The practical implications of this approach are discussed and techniques for proving properties of optimal fixed poin t are given. The presentation is informal, with emphasis on examples. CACM November, 1977 Manna, Z. Shamir, A. recursive programs, fixed poin ts, least fixedpoints, optimal fixed poin ts, proof techniques 5.24 CA771109 JB December 27, 1977 7:13 AM 2907 5 2907 2907 5 2907 2907 5 2907