clarke@utcsri.UUCP (Jim Clarke) (02/21/86)
(GB = Galbraith Building, 35 St. George Street) (SF = Sandford Fleming Building, 10 King's College Rd.) COLLOQUIUM, Tuesday, March 4, 11 am, SF 1105 Professor A. von Staa Catholic University of Rio de Janeiro "The Computer Environment in Brazil" (Abstract below.) SYSTEMS/AI SEMINAR, Tues. Mar. 4, 3 pm, SF 1105 Dr. Joseph Goguen SRI International "Eqlog - the Software Specification and Logic Programming Language" (Abstract below.) THEORY SEMINAR, Tues. Mar. 4, 4 pm, SF 1105 Dr. Erich Kaltofen Rennselaer Polytechnic Institute "Computing with Polynomials given a Straight-Line Programs Theory and Practice" (Abstract below.) SYSTEMS SEMINAR, Thurs. Mar. 6, 11 am, GB 220 Yannis Ioannidis University of California, Berkeley "Processing Recursion in Deductive Databases" (Abstract below.) AI SEMINAR, Thurs., Mar. 6, 3 pm, SF 1101 Edward P. Stabler, Jr. Quintus Computer Systems "Restricting Logic Grammars" (Abstract below.) SPECIAL ANNOUNCEMENT This year's Keys Memorial Lecture will be given by Dr. Lewis M. Branscomb, IBM Chief Scientist and Vice-President on the subject "Smart Machines or Satisfying Ones: the Promise of Artificial Intelligence", on Monday, 3 March 1986 at 4:00 pm in the George Ignatieff Theatre. ABSTRACTS Arndt von Staa An Assessment and Outlook of the Computer Industry in Brazil Several years ago Brazil decided to start its own computer industry. For this purpose import restrictions were enacted, especially with regard to micro and mini computers. One of the consequences is a growing hardware industry, where nothing existed before. Computer related activities are still the fastest growing economical branch in Brazil, even at a time of severe recession. For example, there are now more than 40 hardware manufacturers. Some of this hardware is being exported, believe it or not, to the USA. Hardware and software used in bank automation has been entirely designed and developed in Brazil. Some people claim that these systems are the most sophisticated around. There are also several negative aspects, the worst of them is piracy. Some people argue though, that piracy would be even worse if no national com- puter industry existed. Some of the proposed ideas about how to combat piracy will be presented. In this talk some of the existing and proposed laws will be described. Some of the consequences these laws had on the computer industry will be shown. Computer related education, hardware industry, software industry, CAD/CAM, industrial control, computer services will be briefly examined, and an outlook of their evolution will be shown. Joseph Goguen Eqlog Eqlog is a logic programming language for software specification with some nice applications to artificial intelligence such as problem solving and natural language. Erich Kaltofen Computing with Polynomials given by Straight-Line Programs Theory and Practice My talk centers around the theory and practice of a new representation for multivariate polynomials with exponentially many terms, namely the representation by straight-line programs. I have shown that theoretically common polynomial operations are feasible, that is random polynomial-time. More precisely, given polynomials in straight-line format one can, for example, compute the greatest common divisor and the irreducible factors - again in straight-line representation - in random polynomial time (Monte- Carlo, always fast and probably correct). My lecture will focus on the factorization algorithm. We are currently building a system for manipulating polynomials and rational functions in such a representation. Together with a conversion procedure back to sparse format, this system can manipulate objects that previously needed exponential space to represent. I will also demonstrate our system by showing examples, which underline the practicality of our new representation as well. Edward P. Stabler, Jr. Restricting Logic Grammars The best-known parser formalisms for logic programming systems have typi- cally aimed to be expressive and efficient rather than restrictive, but it is well known that more restrictive formalisms can make the task of grammar construction easier, whether it is done manually (by a programmer) or automatically (by a grammar induction system). The ideal would be a parser formalism for natural languages that is so restricted as to rule out the definition of just those linguistic structures that do not occur in any natural language. A restrictive grammar formalism for logic programming languages will be described that imposes some of the constraints suggested by recent Chomskian linguistic theory, constraints that are thought to apply to all human languages. This formalism allows for relatively elegant characterizations of natural languages that can be translated into reason- ably efficient top-down backtracking prolog parsers with lookahead. Yannis Ioannidis Processing Recursion in Deductive Databases Recursion appears to be one of the most important features of a database system enhanced with deductive power. In such an environment, it has trad- itionally been studied under the formalism of 1-st order logic, focus- ing on recursive Horn clauses. We reformulate the recursion problem in operator form, embedding it in a particular algebraic structure. This enables us to get more information about the mechanics of recursion. In particular, alternative processing techniques are revealed, which, depend- ing on the database state, have the potential of being more efficient than the traditional ones. The importance of including these alternative algorithms in the strategy space of a recursion optimizer is illus- trated by some examples. -- Jim Clarke -- Dept. of Computer Science, Univ. of Toronto, Canada M5S 1A4 (416) 978-4058 {allegra,cornell,decvax,ihnp4,linus,utzoo}!utcsri!clarke