Ait-Kaci, H., and Podelski, A. 1993. Towards a Meaning of LIFE. Journal of Logic Programming. Vol.16, pp.195-234.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....They originated in the late seventies with so called unification grammars [15, 13] a by now popular family of declarative grammar formalisms for the description and processing of natural language. More recently, the use of feature descriptions in logic programming has been advocated and studied [3, 4, 5, 6, 21]. Essentially, feature descriptions provide a logical version of records, a data structure found in many programming languages. Feature descriptions have been proposed in various forms with various formalizations [1, 2, 14, 18, 11, 20, 7, 12] We will follow the logical approach pioneered by ....

H. Ait-Kaci and A. Podelski. Towards a meaning of LIFE. In J. Maluszy'nski and M. Wirsing, editors, Proceedings of the 3rd International Symposium on Programming Language Implementation and Logic Programming, Springer LNCS vol. 528, pages 255--274. SpringerVerlag, 1991. 30

....word is more specific than the corresponding concept (if there is one) in the upper semantic bound. 8 Implementation We have developed a sentence generator called PROTECTOR (approximate PROduction of TExts from Conceptual graphs in a declaraTive flamewORk) PROTECTOR is implemented in LIFE [1]. The syntactic coverage of the gener ator is influenced by the XTAG system (the first version of PROTECTOR in fact used TAGS) By using DTGs we can use most of the analysis of XTAG while the generation algorithm is simpler. We are in a position to express subparts of the input semantics as ....

H. A[t-Kaci and A. Podelski. Towards a meaning of LIFE. Journal of Logic Programming, 16(3&:4):1952.

....of FT with existential quantification to Rabin s famous theorem on tree automata. Keywords Feature logic, tree orderings, entailment, decidability, complexity, second order monadic logic. 1 Introduction Feature constraints have been used for describing records in constraint programming [1, 23, 22] and record like structures in computational linguistics [12, 11, 21, 17, 19] Following [2, 4, 3] we consider feature constraints as predicate logic formulae interpreted in the structure of feature trees. We consider the system FT of ordering constraints over feature trees [16, 13] which is as ....

....FT and in FT . For instance, both trees in the picture above are possible denotations for x in solutions of the constraint wine(x) x[color]x red(x ) It is well known that the first order theory of FT is decidable [4] and that several of its fragments can be decided in quasi linear time [1], including the satisfiability problem of FT and its entailment problem with existential quantification j j=9x 1 : 9x n j . Much less is known on the first order theory of FT . The entailment problem j j= j of FT has been shown to have cubic time complexity in [16] It is however not ....

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H. At-Kaci and A. Podelski. Towards a Meaning of Life. The Journal of Logic Programming, 16(3 and 4):195--234, July, Aug. 1993. 14

.... 23, 38, 40] These are a class of feature description logics, and, as such, have a long tradition in knowledge representation and in computational linguistics and constraintbased grammars [31, 36] More recently, they have been used to model record structures in constraint programming languages [2, 33, 37, 38]. We use feature trees to represent types. Feature trees can naturally represent the types of all kinds of data structures with labeled components such as object, record, or message types. A base type like int is a feature tree with label int and no features. A message type msg( f 1 :t 1 ; ....

H. At-Kaci and A. Podelski. Towards a meaning of life. The Journal of Logic Programming, 16(3--4):195--234, July, Aug. 1993.

....This notation is common in the literature on feature trees. as such, have a long tradition in knowledge representation and in computational linguistics and constraint based grammars [21, 24] More recently, they have been used to model record structures in constraint programming languages [2, 25, 26]. The constraint language of our system OF is this one: j : jj j x = y j a(x) j x[ f ]y j F(x) j xhyiz The first three constraints are the usual ones: The symbol = denotes equality on feature trees, a(x) holds if x denotes a feature tree that is labeled with a at the root, and x[ f ]y ....

H. At-Kaci and A. Podelski. Towards a meaning of life. J. of Logic Programming, 16(3 -- 4):195-- 234, July, Aug. 1993.

.... incremental treatment of rules arguments, i.e. interleaving arguments processing with (parsing oriented) control operations. The analogy with the name of LIFE Logic, Inheritance, Functions and Equalities a well known constraint logic language based on the OSF constraint system [4] is evident. LIFE was intended (but not limited) to be used in NLP applications [3] However, up to our knowledge, no large scale application was implemented in LIFE. An order and type consistent set of FSs is more general than a well typed since it supports: i: open FSs, ii: the de nition of ....

....for rules compilation. R0: intersect sort X[0] vp ext. S1 test feature X[0] ARGS, X[1] 1, W1, vp intersect sort X[1] cons S1 test inst list X[1] 2, W2 get first X[1] X[2] intersect sort X[2] verb test feature X[2] HEAD, X[3] 3, W3, verb R1: test feature X[2] OBJECT, X[4], 3, W4, verb intersect sort X[4] np R2: test feature X[2] SUBJECT, X[5] 3, W5, verb R3: get rest X[1] X[6] S2 intersect sort X[6] cons test inst list X[6] 3, W7 unify first X[6] X[4] test NIL rest X[6] S3 R4: unify feature X[0] HEAD, X[3] LHS read unify feature X[0] ....

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H. At-Kaci and A. Podelski. Towards a meaning of LIFE. Journal of Logic Programming, 16:195{ 234, 1993.

.... a Feature Constraint System and its Extension to a Logic Concurrent Language Liviu Virgil Ciortuz DFKI, LT Lab, Stuhlsatzenhausweg 3, Saarbrucken, Germany. E mail: ciortuz dfki.de. Abstract. This paper presents a feature constraint system that, compared with the well known systems OSF[1] and CFT[5] incorporates several interesting characteristics. The new system, called DF, is naturally extended through the CLP scheme (in combination with a dynamic completion technique) to a logic language equally called DF. The DF feature constraint system adopted the F logic s [4] ....

....in a concurrent flavoured manner, with a completely rebuilt operational semantics. 1 Introduction Feature constraint systems, a subject stemming from the logic perspective on Natural Language Processing have been proven fruitful for the development of new logic constraint languages as LIFE [1] and Oz [6] LIFE is a logic language based on the OSF constraint system. It has a flavor of concurrency, due to a suspension mechanism triggered on function application, that causes waiting suspension of the resolution process until goal variables (that once caused unification failure) become ....

H. Ait-Kaci and A. Podelski. Towards a meaning of LIFE. Journal of Logic Programming, 16:195--234, 1993.

....types , a very convenient way to describe in a concise manner classes of rules and lexical entries. Di erent logical perspectives on such a grammar design were largely studied; see [3] for a survey. For the LIGHT parsing system we adopted the Order Sorted Feature (OSF) constraint logic framework [2]. In this way, typed uni cation grammars may be seen as a generalisation of De nite Clause Grammars (DCG, 7] similar to the way in which LOGIN generalised Prolog [1] The aim of our work is to explore the usefulness of a logic based learning approach namely Inductive Logic Programming ....

....some rule or lexical type feature structures (FSs) in the grammar so to make it accept a given sentence parse tree, or try to specialise a certain type in the grammar so to reject a (wrongly accepted) parse. As a matter of terminology, the terms in LOGIN, or OSF terms as they were re named in [2], correspond to Feature Structures in the Natural Language Processing (NLP) and Computational Linguistics (CL) literature. OSF terms generalise rst order terms in the following respects: i. constant symbols ( sorts ) are organised into a hierarchy, assumed to be an inferior semi lattice; ii. ....

H. At-Kaci and A. Podelski. Towards a meaning of LIFE. Journal of Logic Programming, 16:195-234, 1993.

....of the LIGHT language and system. Besides, we consider that the possibilities for improving the LIGHT system s implementation are far from exhaustion. This is why we found appropriate to publish this overview work about LIGHT. LIGHT has a fairly elegant logic design in the framework of OSF logic [4]. The LIGHT name is an acronym for Logic, Inheritance, Grammars, Heads, and Types. Distinctive from the other systems processing LinGO like grammars, LIGHT uses OSF theory uni cation [5] on order and type consistent theories. This class of OSF logic theories extends well typed systems of ....

....type consistent OSF theories satisfying a set of appropriateness constraints concerning every feature s value and domain of de nition. The analogy with the name of LIFE Logic, Inheritance, Functions and Equalities a well known constraint logic language based on the OSF constraint system [4] is evident. For non lexicalized typed uni cation grammars, top down inferences can be conveniently de ned, and in this case LIGHT would be seen as a particular CLP(OSF) language. For the CLP schema see [18] It is in fact in this way that LIGHT was rst implemented, before it was converted ....

H. At-Kaci and A. Podelski. Towards a meaning of LIFE. Journal of Logic Programming, 16:195-234, 1993.

....hierarchies, a very convenient way to describe in a concise manner classes of rules and lexical entries. Di erent logical perspectives on such a grammar design were largely studied; see [2] for a survey. For the LIGHT system we adopted the Order Sorted Feature (OSF) constraint logic framework [1]. The aim of our work is to explore the usefulness of a logic based learning approach namely Inductive Logic Programming (ILP) to improve the coverage of a given typed uni cation grammar: either generalise some (automatically identi ed) rule or lexical type feature structures (FSs) in the ....

H. At-Kaci and A. Podelski. Towards a meaning of LIFE. Journal of Logic Programming, 16:195-234, 1993.

....Proceedings of the International Workshop on Parsing Technologies (pp. 90 100) held at Beijing University, China, 17 19 October, 2001. The analogy with the name of LIFE Logic, Inheritance, Functions and Equalities a well known constraint logic language based on the OSF constraint system [1] is evident. The conception and implementation side of the work here reported was done while the author was employed at the LT Lab of the German Research Center for Arti cial Intelligence (DFKI) in Saarbr ucken, Germany. These most probable failure paths are identi ed by running the system ....

....then no space (otherwise needed in an interpreter framework) for constructing the FS corresponding to the rule s complement non key argument is wasted. This strategy of incremental parsing in Light which is simple and elegant due the use of open records FSs as in the OSF constraint theory [1], in contrast with closed records used in the appropriateness based approach [3] underlying other LinGO parsing systems provided us a factor of speeding up of 2.75 on the test suite provided by the CSLI, University of Stanford. Note that even in the hyper active head corner parsing approach ....

H. At-Kaci and A. Podelski. Towards a meaning of LIFE. Journal of Logic Programming, 16:195-234, 1993.

.... then to CFT [23] by incorporating arity constraints, and was finaly chosen to underlie the concurrent constraint object oriented language Oz [20] On the other side, feature constraints were used to express in a powerfull way logic records generalizing first order terms, namely terms [2] [3] [7] allowing for the sound use of the inheritance principle in the area of logic programming. This paper aims to enhance the previously mentioned work by reconsidering a (more complete) attempt to express the object orientation paradigm in logic, namely F logic [16] We preserve the F logic ....

H. Ait-Kaci, A. Podelski, Towards a meaning of LIFE, Journal of Logic Programming, 1993:16:195-234.

....compiling HPSGs into Oz. logic Data Frame based Language for HPSGs implementation. DFL is built on top of a constraint system remaking the F logic operational semantics [7] It offers an expressive way to reason on frame data structures extending in some particular respects the Ait Kaci s terms [1] and Smolka and Treinen logic records [12] An interpreter for DFL has already been written in Oz, and a compiler translating DFL logic programs to Oz is currently implemented at LIFL, France. The second section of this paper presents the link between HPSGs and DFL, while the third one links DFL ....

.... ( headDtr [phon 2] i 7 7 7 7 7 7 7 7 5 Fig. 1. A HPSG sign OSF was the first constraint system conceived to reason on order sorted feature constructs [2] It conceptualizes LIFE, an extension of Prolog with (unification on) terms over an apriori given sort hierarchy [1]. Then OSF was followed by CFT, the base constraint system in Oz [3] Making use of the terminology in [7] we can say that while The n marks are tags, denotes string concatenation, the brackets enclose different values for multiple valued features, is the anonymous tag, and ( enclose ....

H. Ait-Kaci, A. Podelski, Towards a meaning of LIFE, Journal of Logic Programming, 1993:16:195-234.

....on the GRlearnt grammar, will be orthogonal. Light system registered a reduction of the uni cation time that sped parsing up to 23 . 2 Generalised Reduction De nitions From the logical point of view, FSs can be viewed as positive OSF clauses, which are nite sets of atomic OSF constraints [2] sort constraints, feature constraints and equation constraints. Therefore the generalisation of FSs can be logically achieved through elimination of some atomic constraints from the FS. We showed in [6] how one can improve the linguistic competence i.e. enhancing the coverage of a given ....

....the parsing results on a large corpus test suite. Note that although GR explicitly eliminates only feature constraints, it may be the case that sort and or equation constraints associated with the value of an eliminated feature constraint get implicitly eliminated through FS normalisation [2]. We make the observation that the notion of restriction in the HPSG literature designates the elimination of certain (few) features following the application of a parsing rule. Generalised Reduction extends this operation on arbitrary chosen features (of course, ensuring the parsing correctness ....

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H. At-Kaci and A. Podelski. Towards a meaning of LIFE. Journal of Logic Programming, 16:195-234, 1993.

....GR learnt grammar, will be orthogonal. LIGHT system registered a reduction of the unifica tion time that sped parsing up to 23 . 5 2 Generalised Reduction Definitions From the logical point of view, FSs can be viewed as positive OSF clauses, which are finite sets of atomic OSF constraints [2] sort constraints, feature con straints and equation constraints. Therefore the generalisation of FSs can be logically achieved through elimination of some atomic constraints from the FS. We showed in [6] how one can improve the linguistic competence i.e. enhancing the coverage of a ....

....the parsing results on a large corpus test suite. Note that although GR explicitly eliminates only feature constraints, it may be the case that sort and or equation constraints associated with the value of an eliminated feature constraint get implicitly eliminated through FS nor malisation [2]. We make the observation that the notion of re striction in the HPSG literature designates the elimination of certain (few) features following the application of a parsing rule. Generalised Reduction extends this operation on arbitrary chosen features (of course, ensuring the parsing ....

[Article contains additional citation context not shown here]

H. AYt-Kaci and A. Podelski. Towards a meaning of LIFE. Journal of Logic Programming, 16:195-234, 1993.

....[25, 27, 49] In programming languages, attribute value combinations are used in record structures. At Kaci was the first to study such structures mathematically, calling them # terms [2] The resulting term calculus is the formal foundation of the programming languages LOGIN [3] and LIFE [4], which are similar to PROLOG, but use feature unification [51] instead of syntactic unification. In contrast to several description logics, attributes in terms are functional : they can have only one value. This is convenient, since objects can be identified by some unique attribute value. ....

At-Kaci, H., and Podelski, A. Towards a meaning of LIFE. In Proc. 3rd International Symposium on Programming Language Implementation and Logic Programming (Passau, Germany, Aug. 1991), J. Maluszy nski and M. Wirsing, Eds., vol. 528 of Lecture Notes in Computer Science, Springer-Verlag, pp. 255--274.

.... 217 7 Completeness of the Entailment Test 226 1365 8050 c 2001 Maison de l Informatique et des Mathmatiques Discrtes (MIMD) Paris, France 194 Martin Mller and Joachim Niehren and Ralf Treinen 1 Introduction Feature constraints have been used for describing records in constraint programming [1, 30, 31, 36] and record like structures in computational linguistics [14, 12, 23, 26] Feature constraints also occur naturally in type inference for programming languages with object types or record types [22, 5, 24] Following [2, 4, 3] we consider feature constraints as predicate logic formulas ....

.... sense, i.e. that it is a tree strictly greater than the smallest tree (feg;fg) but with minimal distance (one feature or one label more) one dist(x;y) y x y atom(y) 9x ( x true) one dist(x;y) 198 Martin Mller and Joachim Niehren and Ralf Treinen Example 2 The formula x(x[0]x x[1]x) is satisfied in FT by (f0;1g ; fg) that is the full binary and everywhere unlabeled tree, and is not satisfiable in FT fin since FT fin contains no infinite trees. 3.2 Label Restrictions The formula x y reads x and y are consistent, that is whenever (p;a) 2 L t and (p 0 ; a ....

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H. At-Kaci and A. Podelski. Towards a meaning of Life. The Journal of Logic Programming, 16(3 and 4):195--234, July, Aug. 1993.

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Ait-Kaci, H., and Podelski, A. 1993. Towards a Meaning of LIFE. Journal of Logic Programming. Vol.16, pp.195-234.

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) H. At-Kaci and A. Podelski. Towards a meaning of LIFE. Journal of Logic Programming, pages 195--234, 1993.

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H. At-Kaci & A. Podelski: "Towards a Meaning of LIFE", Proceedings of the Third International Conference on Programming Language Implementation and Logic Programming, Lectures Notes in Computer Science, Passa, August 1991

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