In a 1981 book, H. Putnam claimed that in a pure relational language without equality, for any model of a relation that was neither empty nor full, there was another model that satisses the same rst order sentences. Ed Keenan observed that this was false for nite models since equality is a deenable predicate in such cases. This note shows that Putnam's claim is true for innnite models, although...

We are concerned with fractional powers of the so-called hyponormal operators of Putnam type. Under some suitable assumptions it is shown that if A, B are closed hyponormal linear operators of Putnam type acting on a complex Hilbert space H, then D((A+B)α) = D(Aα)∩D(Bα) = D((A+B)∗α) for each α ∈ (0,1). As an application, a large class of the Schrödinger’s operator with a complex potential Q ∈ L...

This paper summarizes the author's paper (presented in KR-94 and titled \Directional Resolution: The Davis-Putnam Procedure, Revisited" [Dechter and Rish, 1994]), focusing on its empirical aspects. It compares a resolution based variant of the Davis-Putnam algorithm with a backtracking variant and highlights their sensitivity (or insensitivity) to the problems' structure. Experiments show that ...

Frank W. Putnam, M.D., is Professor of Pediatrics and Psychiatry at Cincinnati Children’s Hospital Medical Center, University of Cincinnati College of Medicine. In 1999, he became Director of the Mayerson Center for Safe and Healthy Children, which is dedicated to improving services for traumatized children and their families. Dr. Putnam is the author of over 140 scientific publications and two...

This paper presents a statistical analysis of the Davis-Putnam procedure and propositional satisfiability problems (SAT). SAT has been researched in AI because of its strong relationship to automated reasoning and recently it is used as a benchmark problem of constraint satisfaction algorithms. The Davis-Putnam procedure is a wellknown satisfiability checking algorithm based on tree search tech...