R.T. Kasper and W.C. Rounds. A logical semantics for feature structures. In Proceedings of the 2.e Annual Meeting of the Association for Computational Linguistics (ACL-86), pages 235--242, 1986.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....features, which are functional attributes. Figure 1, for instance, shows the description of a linguistic object that may represent the sentence John sings a song . The features appear as edges of the graph. The terminal nodes are atoms representing primitive linguistic objects. Kasper and Rounds [10, 17] were the first to capture the relation between feature descriptions and linguistics objects in terms of a logic. Subsequently, Johnson [6] and Smolka [22, 23] realized that feature logics can be modeled straightforwardly in Predicate Logic. In this approach, which underlies the present paper, ....

....is simply a structure that interprets atoms as pairwise distinct individuals and features as unary partial functions that are undefined on atoms. In addition, one can have sorts, which are interpreted as sets of individuals. One popular syntax for feature descriptions are so called feature terms [10, 17, 23], which are expressions denoting sets in feature algebras. The basic feature term forms are given by S Gamma a j A j p: S j p#q j S u S j S t S j :S; where a stands for atoms, A stands for sorts, and p and q stand for words over features. Given a feature algebra, a denotes the singleton ....

R. T. Kasper and W. C. Rounds. A logical semantics for feature structures. In Proceedings of the 24th Annual Meeting of the ACL, Columbia University, pages 257--265, New York, N.Y., 1986.

....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 [20] which accommodates feature descriptions as standard first order formulae interpreted in first order structures. In this approach, a semantics for feature descriptions can be given by means of a feature theory (i.e. a set of closed feature ....

R. T. Kasper and W. C. Rounds. A logical semantics for feature structures. In Proceedings of the 24th Annual Meeting of the ACL, Columbia University, pages 257--265, New York, N.Y., 1986.

....In this paper, we introduce the idea. of informa.tion based MT, which is consid era.bly more flexible tha.n interlingual MT or the conventional tra.nsfer based MT. Introduction With the intensive explora.tlon of contemporary theories on unifica.tion gramma.rs[6, 15, 13] and feature structures[7, 19] in the last deca.de, the old ima.ge of machine tra.nsla.tion (MT) as a. bru tal form of naturM language processing has given way to tha.t of a process based on a. uniform a.nd reversible a.rchitecture[16, 1, 27] The developers of MT systems based on the constra.int based formalism found a. ....

Fl.. Kasper stud W. (2. Pounds. "A Logical Semantics for Feature Structures". In Proc. of the gth Annual Meet- trig of the Association for Computational Linguistics, Columbia University New York, NY, June 1986.

....called feature structures [40] or feature terms [46] In contrast to earlier work, the notion feature structure was mostly used for designating a record structure itself [14, 39, 42] rather than a record description. Logical descriptions of record structures lead to the notion of feature logic [25, 23, 46]. When we call these descriptions feature constraints, feature unification becomes constraint solving. Two main approaches to feature logics should be clearly distinguished. In computational linguistics [14, 39, 42] a record structure is traditionally described from an internal perspective, i.e. ....

Robert T. Kasper and William C. Rounds. A logical semantics for feature structures. In Proceedings of the Annual Meeting of the Association of Computational Linguistics, pages 257--265, 1986.

....entailment test has recently received some attention as a justification for constraint simplification and as a means to check type interfaces [4, 9, 10, 14, 22, 32] Originally, weak subsumption has been introduced as a weakening of subsumption. The subsumption ordering between feature structures [5, 12, 26] is omnipresent in linguistic theories like HPSG (head driven phrase structure grammar) 21] According to the more general view of [6, 27] the subsumption ordering and the weak subsumption ordering are definable between elements of an arbitrary feature algebra (not only between feature ....

R. T. Kasper, W. C. Rounds. A logical semantics for feature structures. In Annual Meeting of the Association of Computational Linguistics, 257--265, 1986.

....shown that determining consistency of terms is a NP complete problem. Subject Areas: feature logic, constraint based gram mars, HPSG 1 Introduction Grammatical formalisms such as HPSG [Pollard and Sag, 1987] Pollard and Sag, 1992] and LFG [Kaplan and Bresnan, 1982] employ feature descriptions [Kasper and Rounds, 1986] [Smolka, 1992] as the primary means for stating linguistic theories. However the descriptive machinery employed by these formalisms easily exceed the descriptive machinery available in feature logic [Smolka, 1992] Furthermore the descriptive machinery employed by both HPSG and LFG is difficult ....

....employed for the modelling of so called semantic indices ( Pollard and Sag, 1987] pp. 104) The attribute INDS in the example in (1) is a multi valued attribute whose value models a set consisting of (at most) 2 objects. However multi valued attributes cannot be descri bed within feature logic [Kasper and Rounds, 1986] [Smolka, 1992] 1) rv 1 rv. 1 xs IStl II lstl m II L L JJL L ]J A further complication arises since to be able to deal with aphoric dependencies we think that set memberships will be needed to resolve pronoun dependencies. Equally, set unions may be called for to incrementally construct ....

Robert Kasper and William Rounds. A logical semantics for feature structures. In 2Jth Annual Meeting of the Association for Computational Linguistics, Columbia University, New York, pages 257-265, 1986.

....interpretation. The longer term goal is to incorporate such representations into an appropriate general framework for natural language processing. One of the dominant paradigms in current computational linguistics is provided by uni cation based grammar formalisms. Such formalisms (cf. [Shi86, KR86]) describe hierarchical feature structures, which in many ways would be appear to be an ideal setting for formal phonological analyses. Feature bundles The work reported in this paper has been carried out as part of the research programmes of the Dyana project (br 3175) funded by cec esprit, ....

Kasper, R. & W. Rounds (1986). A Logical Semantics for Feature Structures. Proceedings of the 24th Annual Meeting of the ACL, Columbia University, New York, NY, 1986, pp257-265.

....to understand. For disjunctive feature de scriptions, Kay[14] introduces them into FUG (Fmc tonal Unification Grammar) aml gives the procedu ral semantics. Karttnnen[11] also proposes proce dural treatments of disjunctious in conjunction with relatively simple negations. Rounds and l(a. Sl)er[19 , 13] propose a logic based formalism feature logic ,tuch uses autonmta to model FSs and can treat dis .tunetire feature descriptions, and they obtain impor tent results. or negative descriptions of FSs, one of the most fundamental properties of FSs, the partiality of information they carry, ....

Robert T. Kasper and William C. Rmmds. A logi- cal semantics for feature structure. Is Proceedings of the 4th Annual Meeting o-[ the Assaeration.tar Computational Lin#uistics, ACL, New York, New York, USA, 1986.

....relates several trees. Both views have a long tradition in logics. The internal view is taken in modal logic and in second order monadic logic (SnS) Rab69] whereas the external view is popular in uni cation theory [MM82,Col84,BS93] and for set constraints [HJ90,AW92,TDT00] In feature logics [KR86,Smo92], both perspectives have been employed and compared [BS95,MN00] Dominance versus Subtree Constraints. Dominance constraints contain node valued variables that we write as capital letters X;Y; Z. An atomic dominance constraint X Y holds in a tree (structure) if the node denoted by X is above ....

Robert T. Kasper and William C. Rounds. A logical semantics for feature structures. In Annual Meeting of the Association of Comp. Linguistics, pages 257-265, 1986.

....[46] and Johnson s Attribute Value Logic [16] employ boolean combinations of equations built from features (used as unary functions) atoms (used as constants) and variables. Kay s Functional Unification Grammar [24, 25, 26] Ait Kaci s Term Calculus [2, 3, 4] and Kasper and Rounds logic [23, 39] employ set denoting expressions, called feature terms in this paper, that come in different syntactic guises (Figure 2 gives an example) Feature terms have much in common with the concept descriptions of terminological logics [5, 33, 34] used in knowledge representation. In fact, Ait Kaci s ....

....the edges departing from it must be pairwise distinct. Moreover, every inner node of a feature graph must be a variable, and every terminal node must be either an atom or a variable. Feature graphs can be seen as finite deterministic automata, which is the formalization given by Kasper and Rounds [23, 39]. In contrast to Kasper and Rounds, however, we admit cyclic feature graphs. Formally, an f edge from x to s is a triple xfs such that x is a variable, f is a feature, and s is either a variable or an atom. A feature graph is either a pair (a; where a is an atom and ; is the empty set, or a ....

[Article contains additional citation context not shown here]

R. T. Kasper and W. C. Rounds. A logical semantics for feature structures. In Proceedings of the 24th Annual Meeting of the ACL, Columbia University, pages 257-- 265, New York, N.Y., 1986.

....such results as a sign that existing feature logics treat linguistic structure too homogeneously. What is needed are feature log ics which are more sensitive to the fine structure of linguistic theorising. The paper is relatively self contained, nonetheless the reader may find it helpful to have [Kasper and Rounds 1986, 1990] and [Blackburn and Spaan 1991, 1992] to hand. 2 Preliminaries Feature logics are abstractions from the unification based formalisms of computational linguistics. Originally feature logics embodied just one component of unification based formalisms. Early unifica tion formalisms such as ....

Kasper, R. and Rounds, W.: 1986, A logical semantics for feature structures, in Proceedings of the Jth Annual Meeting of the Association for Computational Linguistics, Columbia University, New York, 257-266.

....common practice to reason about the properties of formalisms for linguistic description within the framework of formal logic. A number of first order theories have been proposed to serve the purpose, ranging from classical first order predicate calculus to numerous variants of non classical logics [RK86, KR86] elsewhere dubbed designer logics [Joh90] These latter approaches have been criticized for cutting the field o# the wealth of results in classical logic without real benefits since it has never been shown that any of the non classical devices proposed was indeed necessary [Joh90] The same ....

Kasper, Robert and William Rounds. 1986. A logical semantics for feature structure. In : ACL Proceedings, 24th Annual Meeting, 257--266.

....descriptions to those rst order sentences which are equivalent to a sentence of the form 9x 1 : xn8y 1 : ym , where does not contain function symbols. 16) is of this form. This fragment has nice computational properties and may function as an alternative to the feature logic of [16]. In [4] the author limits expressivity by using a modal logic to describe linguistic structures. Since most linguistic structures are graphs and since modal logics are tailored to reason about graphs (in the guise of Kripke models) this proposal is very natural. The LFG description in (15) could ....

R. Kasper and W. Rounds. A Logical Semantics for Feature Structures. In Proc. 24th meeting of the ACL, pages 101-115, 1986.

....entailment test has recently received some attention as a justification for constraint simplification and as a means to check type interfaces [24, 5, 35, 16, 10, 11] Originally, weak subsumption has been introduced as a weakening of subsumption. The subsumption ordering between feature structures [13, 28, 6] is omnipresent in linguistic theories like HPSG (head driven phrase structure grammar) 23] According to the more general view of [29, 7] the subsumption ordering and the weak subsumption ordering are definable between elements of an arbitrary feature algebra (which include the structure of ....

R. T. Kasper and W. C. Rounds. A logical semantics for feature structures. In Annual Meeting of the Association of Computational Linguistics, pages 257--265, 1986.

....of a grammar are the well formed phrases of the language. 38 We will illustrate the way in which Case, agreement, and unbounded dependency are handled in a feature structure grammar by using Pollard and Sag s (1994) HPSG. The HPSG 38 For the formal foundations of feature structure grammars see Kasper and Rounds (1986) and (1990) Johnson (1988) Carpenter (1992) Keller (1993) and Rounds (forthcoming) 34 attribute value graph for 2a is 31. 39 2a. John saw Mary. 31. PHON John, saw, Mary CAT HEAD 3 ( S[fin,past] SUBCAT PHON saw, Mary ....

Kasper, R. and W. Rounds (1986), "A Logical Semantics for Feature Structures", Proceedings of the 24th Annual Conference of the A ssociation for Computational Linguistics, New York, pp. 235-242.

....of structures defined within a specific formal framework. Now, properties of classes of structures that are defined in some formal way are the provenance of Model Theory. It s not surprising, then, to find treatments of the meaning of such systems of constraints couched in terms of formal logic [KR86, MR87, KR90, GPC 88, Joh88, Smo89, DVS90, Car92, Kel93] More recently, the role of logic has begun to expand beyond just providing formal semantics for the constraints to provide the entire linguistic formalism. See, for instance, Joh89, Sta92, Cor92, BGMV93, BMV94, Kel93, Rog94, Kra95] ....

Robert T. Kasper and William C. Rounds. A logical semantics for feature structures. In Proceedings of the 24th Annual Meeting of the Association for Computational Linguistics, 1986.

.... to be interpreted strongly in the sense that for some categories A and BA B is considered true only in the case when neither A nor B can be inferred, but the disjunction A B is true [35] Ordinary unification is almost linear in time complexity [39] whilst disjunctive unification is NP complete [31]. The formalism used is (apart from the notational use of disjunction) a variant of the PATR II formalism [48] PATR II is intended to be a tool formalism and so can be used to simulate most other unification based formalisms. 3.2 System architecture We assume that the system has some initial ....

Robert T. Kasper and William C. Rounds. A logical semantics for feature structures. In 24th Annual Meeting of the Association for Computational Linguistics, pages 257--266, 1986.

....in which the notational resources of FUG may be improved. In particular, FUG has limited notatlonal resources for pressing conditlonal information. In this paper we describe how FUG has been enhanced by the addition of conditional descriptions, building on research that has already been r ported [Kas87a,Kas86,Kas87b]. Conditional information is stated explicltly in systemic grammars by the input conditlons of systems that specify when a system must be used. Consider, for example, the two systems (MoodType and IndicatlveType) x shown in Figure I. The input condition for the MoodType system is the feature ....

....structure; where FDL, denoting conjunction; where FDL, denoting dlsjunctlon. Note: A and L are sets of symbols which are used to denote atomic values and feature labels, respectively. Figure 6: Syntax of FDL Formulas. 2 Definitions The feature description logic (FDL) of Kasper and Rounds [Kas86] provides a coherent framework to give a pre cise interpretatlon for conditional descriptious. As in previous work, we carefully observe the dlstlnction between fea ture structures and their dsecriptlons. Feature structures axe represented by. directed graphs (DGs) and descriptious of feature ....

[Article contains additional citation context not shown here]

Robert. T. Kasper and William O. Rounds. A Log- ical Semantics for Feature Structures. In Proceed- ing of the 24 ta Annual Meeting of the Aociation for Computational inguitic, Columbia University, New York, NY, June 10-13, 1986.

No context found.

R.T. Kasper and W.C. Rounds. A logical semantics for feature structures. In Proceedings of the 2.e Annual Meeting of the Association for Computational Linguistics (ACL-86), pages 235--242, 1986.

No context found.

Robert T. Kasper and William C. Rounds. A logical semantics for feature structures. In Proceedings of the 24th Annual Meeting of the ACL, pages 257--265, New York, NY, 1986.

No context found.

Kasper, R. and Rounds, W.: 1986, A logical semantics for feature structures, in Proceedings of the 24th Annual Meeting of the Association for Computational Linguistics, Columbia University, New York, pp 257-266.

No context found.

Kasper, R. and Rounds, W.: 1986, A logical semantics for feature structures. Proceedings of the 24th Annual Meeting of the Association for Computational Linguistics, Columbia University, New York, pp. 257-266.

No context found.

Kasper, R. and Rounds, W.: 1986, A logical semantics for feature structures. Proceedings of the dth Annual Meeting of the Association for Computational Linguistics, Columbia University, New York, pp. 257-266.

No context found.

Kper R. T_ and Rounds, W. C. 1986, "A Logical Semantics for Feature Structures," 251h AUL Annual Meeting.

No context found.

Kasper, R. T. and W. C. Rounds (1986) `A logical semantics for feature structures', Proceedings of the 24th Annual Conference of the Association for Computational Linguistics (ACL-86), Columbia University, pp. 235--242.

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