PROLOG-REQUEST@SU-SCORE.ARPA (Chuck Restivo, The Moderator) (12/03/86)
PROLOG Digest Thursday, 4 Dec 1986 Volume 4 : Issue 81 Today's Topics: Announcement - Thesis, LP Library - PDProlog & Update ---------------------------------------------------------------------- Date: Wed, 3 Dec 86 13:14 EST From: Tim Finin <Tim@cis.upenn.edu> Subject: Defense Dissertation Defense Computer and Information Science University of Pennsylvania A HIGHER-ORDER LOGIC AS THE BASIS FOR LOGIC PROGRAMMING GOPALAN NADATHUR (gopalan@cis.upenn.edu) The objective of this thesis is to provide a formal basis for higher-order features in the paradigm of logic programming. Towards this end, a non-extensional form of higher-order logic that is based on Church's simple theory of types is used to provide a generalisation to the definite clauses of first-order logic. Specifically, a class of formulas that are called higher-order definite sentences is described. These formulas extend definite clauses by replacing first-order terms by the terms of a typed lambda calculus and by providing for quantification over predicate and function variables. It is shown that these formulas together with the notion of a proof in the higher-order logic provide an abstract description of computation that is akin to the one in the first-order case. While the construction of a proof in a higher-order logic is often complicated by the task of finding appropriate substitutions for predicate variables, it is shown that the necessary substitutions for predicate variables can be tightly constrained in the context of higher-order definite sentences. This observation enables the description of a complete theorem-proving procedure for these formulas. The procedure constructs proofs essentially by interweaving higher-order unification with backchaining on implication, and constitutes a generalisation to the higher-order context of the well-known SLD-resolution procedure for definite clauses. The results of these investigations are used to describe a logic programming language called lambda Prolog. This language contains all the features of a language such as Prolog, and, in addition, possesses certain higher-order features. The uses of these additional features are illustrated, and it is shown how the use of the terms of a (typed) lambda calculus as data structures provides a source of richness to the logic programming paradigm. Thesis Supervisor: Dale Miller Committee: Tim Finin, Jean Gallier (Chairman), Andre Scedrov, Richard Statman ------------------------------ Date: 7 Nov 86 23:25:46 GMT From: David Fiore <ucdavis!ucrmath!hope!fiore@ucbvax.Berkeley.EDU> Subject: PD PROLOG This is in response to all the letters I have recieved requesting PD PROLOG. I have had very little luck responding to the letters, much less getting copies of PD PROLOG to those that wanted it. I am therefore submitting for the second time a copy of PD PROLOG in uuencoded format to the Digest. Good luck with the program! -- David Fiore UseNet : ...!ucdavis!ucrmath!hope!fiore BITNET : consult@ucrvms ------------------------------ Date: Wed 3 Dec 86 11:25:01-PST From: Chuck Restivo <Restivo@Score.Stanford.EDU> Subject: PDProlog [cwr] I left the following files in SCORE:'s Prolog directory. You'll need these to use PDProlog. PS:<PROLOG> PDPROLOG.CODE.2;P775252 75 189686(7) 3-Dec-86 11:14:13 RESTIVO .DOCUMENTATION.2;P775252 24 61299(7) 3-Dec-86 11:15:14 RESTIVO .HELP.1;P775252 1 711(7) 3-Dec-86 11:08:41 RESTIVO .UUDECODE.2;P775252 3 5560(7) 3-Dec-86 11:18:03 RESTIVO .UUENCODE.2;P775252 2 4872(7) 3-Dec-86 11:18:59 RESTIVO -- ed ------------------------------ End of PROLOG Digest ********************