Rmi Zajac. Inheritance and ConstraintBased Grammar Formalisms. Computational Linguistics, 18(2):159-182, 1992. 262  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... 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 (if not impossible) to state in feature based formalisms such as ALE [Carpenter, 1993] TFS [Zajac, 1992] and CUF [DSrre and Dorna, 1993] which augment feature logic with a type system. One such expressive device employed both within LFG [Kaplan and Bresnan, 1982] and HPSG but is unavailable in feature logic is that of set descriptions. Although various researchers have studied set de scriptions ....

Rmi Zajac. Inheritance and ConstraintBased Grammar Formalisms. Computational Linguistics, 18(2):159-182, 1992. 262

....while class morpheme sounds ungrammatically and confusing outside the programming slang. software development [3] Linguistic modeling is not an exception since language is extremely complex and vague system. Object oriented approach in linguistics has been discussed in many recent works [4, 5, 7, 9]. However, these works do not start from the very beginning of the problem: from the discussion of the most abstract linguistic objects, in spite of the practical and theoretical impor tance of this issue. In an object hierarchy always there is the most abstract object 2, the root, which is the ....

Zajac R. Inheritance and Constraint-Based Grammar Formalisms. Computational Linguistics, Vol.18, No.2, 1992. pp. 159-180.

....theory and on the programming language which is used for the implementation. The first question in grammar encoding is which descriptive tools are made available by the given grammar formalism, i.e. by the implementation language. If you use languages like CUF, Prolog [8] or TFS [12] 13] [61] then what you have is essentially a way to The grammar can be obtained via anonymous ftp. Please ask the author for details. HPSG recursion on c structure subcat. principle nonlocal feature principle sem. principle etc. LFG recursion on c structure completeness coherence functional ....

Remi Zajac. Inheritance and constraint-based grammar formalisms. Computational Linguistics, 18(2):159--182, 1992.

....and incorporates a chart parser and lexical rules. It is optimised for speed of processing which, however, makes it less than ideal for a grammar development environment. IMS offers two systems: Comprehensive Unification Grammar (CUF) DE91] written in Prolog, and Typed Feature Formalism (TFS) [Zaj92] in Lisp. Especially CUF offers a very powerful grammar development environment; for a detailed comparison between ALE, CUF and TFS see also [Man93] Finally, it should be noted that of the three systems, ALE is available in source code, the other two being distributed in their compiled version ....

R'emi Zajac. Inheritance and constraint-based grammar formalisms. Computational Linguistics, 18(2), 1992. 11

....Development of Translation Tools: Application to Persian and Turkish Jan W. Amtrup, Karine Megerdoomian and R emi Zajac Computing Research Lab New Mexico State University fjamtrup,karine,zajacg crl.nmsu.edu Abstract The Computing Research laboratory (CRL) is developing a machine translation toolkit that allows rapid deployment of translation capabilities. This toolkit has been used to develop several machine ....

Remi Zajac. 1992. Inheritance and ConstraintBased Grammar Formalisms. Computational Linguistics, 18(2):159-182.

....with loc by employing a disjointness statement such as disjoint(loc,synsem) This makes the grammar harder to read. Hence, the open world interpretation alone is insufficient. 2. closed world The closed world interpretation is provided in systems such as TROLL [ Gerdemann and Gotz, 1994 ] TFS [ Zajac, 1992b ] and CUF (disjunctive spec. In a closed world interpretation, given the subtypes [t 1 ; t 2 ; t 3 ] of a type s; the type s is interpreted as being equivalent to the disjunction t 1 t 2 t 3 i.e. s = t 1 t 2 t 3 . One big advantage of a closed world reasoning interpretation is strong type ....

R'emi Zajac. Inheritance and Constraint-Based Grammar Formalisms. Computational Linguistics, 18(2):159--182, 1992.

.... 1995 ] TAG: Joshi, 1987b ] GB: Webelhuth, 1995 ] CG: Morrill, 1994b ] The following are the key readings for several implemented formalisms: Core Language Engine: Alshawi, 1991 ] CUF: Dorre and Dorna, 1993 ] TDL: Krieger and Schafer, 1994 ] ProFIT: Erbach, 1995 ] TFS: Zajac, 1992a ] For implemented grammars and development environments, there are no introductory readings, but it is possible to refer to the technical reports referenced in chapters 2 and 3. 6.1.4 Other Information Sources The following resources are not concerned exclusively with grammar formalisms, but ....

R'emi Zajac. Inheritance and constraint-based grammar formalisms. Computational Linguistics, 18(2):159--182, 1992.

....and incorporates a chart parser and lexical rules. It is optimised for speed of processing which, however, makes it less than ideal for a grammar development environment. IMS offers two systems 32 : Comprehensive Unification Grammar (CUF) 9] written in Prolog, and Typed Feature Formalism (TFS) [22] in Lisp. Especially CUF offers a very powerful grammar development environment. For a detailed comparison between ALE, CUF and TFS see also [18] Finally, it should be noted that of the three systems, ALE is available in source code, the other two being distributed in their compiled versions ....

R'emi Zajac. Inheritance and constraint-based grammar formalisms. Computational Linguistics, 18(2), 1992. 15

....for example edges built by a tokenizer, morphological analyzer, or a syntactic parser, and de ne sub graphs of the whole chart that are input to some component. Linguistic information on edges is encoded using a weaker version of the Typed Feature Structure formalism as presented for example in [Zajac 92a] Using a centralized data structure has several advantages: a chart gives a precise idea on the state of the system at any point in the computation, and integrating components to build larger systems become easy since all components implement the same interface. In this architecture, all ....

Remi Zajac (1992). Inheritance and Constraint-based Grammar Formalism. Computational Linguistics 18(2), pp 159-182.

....in our project is based. 1 Although ALEP is a typed feature formalism offering an attractive integrated grammar development environment it offers only a very impoverished typed feature logic in comparison to other systems such as ALE [Carpenter and Penn, 1994] CUF [Dorna et al. 1994] and TFS [Zajac, 1992]. It is uncontroversial to say that there is still a gap between the high level descriptions used by linguists and the expressive means of current grammar formalisms such as ALE, ALEP, CUF and TFS. This is especially true for the kinds of descriptions that are offered by relatively low level ....

Remi Zajac. Inheritance and Constraint-Based Grammar Formalisms. Computational Linguistics, 18(2):159--182, 1992.

....feature structure is assigned a type. These types become an integral part of the inference mechanism. In response to the idea of deductive computation in the context of typed feature structures, a number of specialized programming languages have evolved. Among the most visible are TFS [Zaj91] [Zaj92], ALE [Car92a] and CUF [DD93] Recently, a similar system, LKB, has arisen from the ACQUILEX project [BdPC93] In addition, the programming language LIFE [AP93] Ait93] and its predecessor LOGIN [AN86] although not specifically designed for linguistic knowledge representation and manipulation, ....

Zajac, R., "Inheritance and constraint-based grammar formalisms," Computational Linguistics, 18(1992), pp. 159--182.

....for the translation from French to German. Of course, the individual modules can be part of different configurations for other purposes. 2 This differs from an approach to reversibility where there is only one general interpreter for all the descriptive components together, cf. Zajac 1992 [18]. 8 contextUDRS concept definitions UDRS theorem prover UDRS transfer realizer UDRS lexicon grammar parser transfer relations generator lexicon grammar source target French German Figure 2: System architecture for translation from French to German (line: data access; arrow: ....

Remi Zajac. Inheritance and constraint-based grammar formalisms. Computational Linguistics, 18(2):159--182, 1992. 14

....proposals considered the integration of functional and relational dependencies into formalisms which makes them Turing complete in general. 4 However the most important extension to formalisms consists in the incorporation of types, for instance in modern systems like TFS [ Emele Zajac 90; Zajac 92 ] CUF [ Dorre Eisele 91; Dorre Dorna 93 ] or TDL [ Krieger Schafer 93a; Krieger Schafer 94a; Krieger Schafer 94b ] 5 Types are ordered hierarchically (via subsumption) as in object oriented programming languages. This leads to multiple inheritance in the description of linguistic ....

....bagel 3 7 5 3 7 7 7 7 3.4 Type Expansion and Control 25 Type expansion together with a sufficiently specified grammar then is responsible in both cases for constructing a fully specified feature structure which is maximal informative and compatible with the input structure. However, Zajac 92 ] has shown that type expansion without sophisticated control strategies is in many cases inefficient and moreover does not guarantee termination. 3.4.2 Controlled Type Expansion Uszkoreit introduced in [ Uszkoreit 91 ] a new strategy for linguistic processing called controlled linguistic ....

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R'emi Zajac. Inheritance and Constraint-Based Grammar Formalisms. Computational Linguistics, 18(2):159--182, 1992.

.... proposals consider the integration of functional relational dependencies into the formalism which make them, in general, Turing complete (e.g. ALE; cf. 6] However the most important extension to formalisms consists of the incorporation of types , for instance in contemporary systems like TFS [20], CUF [8] ALE, or TDL [11] Types are ordered hierarchically as it is known from object oriented programming languages. This often leads to multiple inheritance in the description of linguistic entities. If a formalism is intended to be used as a stand alone system, it must implement recursive ....

R'emi Zajac. Inheritance and constraint-based grammar formalisms. Computational Linguistics, 18(2):159--182, 1992. This article was processed using the L a T E X macro package with LLNCS style

....power of the first unification based formalisms with different forms of disjunctive descriptions. Later, other operations came into play, e.g. classical) negation. However the most important extension to formalisms consists of the incorporation of types , for instance in modern systems like TFS [ Zajac 1992 ] CUF [ Dorre and Dorna 1993 ] or TDL [ Krieger and Schafer 1994 ] Types are ordered hierarchically as is known from object oriented programming languages, a feature heavily employed in lexicalized grammar theories like Head Driven Phrase Structure Grammar (HPSG) Pollard and Sag 1987 ] ....

.... independent of the underlying deduction system we are not interested in the normalization of feature constraints (i.e. how unification of feature structures is actually done) nor are we interested in the logic of types, e.g. whether the existence of a greatest lower bound is obligatory (TFS [ Zajac 1992 ] ALE [ Carpenter and Penn 1994 ] or optional as in TDL [ Krieger and Schafer 1994 ] We assume here that typed unification is simply a black box and can be accessed through an interface function (say unify tfs) From this perspective, our expansion mechanism can be either used as a ....

[Article contains additional citation context not shown here]

R'emi Zajac. Inheritance and constraint-based grammar formalisms. Computational Linguistics, 18(2):159--182, 1992.

.... proposals consider the integration of functional relational dependencies into the formalism which make them in general Turing complete (e.g. ALE; cf. 5] However the most important extension to formalisms consists of the incorporation of types , for instance in contemporary systems like TFS [20], CUF [7] ALE, or TDL [11] Types are ordered hierarchically, as it is known from object oriented programming languages. This often leads to multiple inheritance in the description of linguistic entities. If a formalism is intended to be used as a stand alone system, it must also implement ....

R'emi Zajac. Inheritance and constraint-based grammar formalisms. Computational Linguistics, 18(2):159--182, 1992. This article was processed using the L a T E X macro package with LLNCS style

....right at the beginning of this report that we borrowed the definitions of these notions from Gerdemann (1995) the most explicit work on this topic (within NLP) that we came across. 2 TFS 2. 1 Introduction The Typed Feature Structure representation formalism, cf. Emele and Zajac (1990b) and Zajac (1992), was developed by Martin Emele and R emi Zajac within the German Polygloss project at IMS, University of Stuttgart. The following description presents briefly the main ideas of the system, Emele (1993) The Typed Feature Structure (TFS) representation formalism is an attempt to provide a ....

....type definitions is the only possibility. However, all type constraints have to be unfolded in the final solution since they all contribute to grammaticality checking. In general, type expansion may be inefficient and can cause termination problems (as in the case of recursive avm types) (Zajac, 1992). T DL provides sophisticated tools for the control of type expansion. Every feature structure can be associated with the success failure potential for unification and the order of type expansion can depend on this information: in conjunctions, constraints with the highest failure probability are ....

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Zajac, R. (1992). Inheritance and constraint-based grammar formalisms. Computational Linguistics, 18(2), 159--182.

....EH8 9LW U.K. 1 Introduction CUF (see [DD93] is one amongst the current breed of typed feature logic based formalisms which are principally targeted at providing a computational system for implementing HPSG grammars. We provide a theory neutral comparison of CUF against the formalisms TFS [Zaj92][Zaj91] and ALE [Car93] drawing out the similarities and differences. Our comparison will be concentrated mainly on the expressivity of the type system, definite clauses and control scheme which provide additional control over the SLD resolution engine. 2 Type System The HPSG grammar formalism is ....

....in a drastically reduced search space since those nondeterministic branches that can be pruned with the aid of deterministic information are eliminated. TFS also employs a delaying scheme that delays goals until the variable (upon which the goal is delayed) is sufficiently instantiated (see [Zaj92]) resorting to a Prolog like strategy when all goals are delayed. 4.1 Delay Statements Finer control of the resolution strategy is achieved in CUF by employing delay statements defined by the user. Delay statements in CUF state the features which need to be instantiated in order that the ....

R'emi Zajac. Inheritance and Constraint-Based Grammar Formalisms. Computational Linguistics, 18(2):159--182, 1992.

.... 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 (if not impossible) to state in feature based formalisms such as ALE [Carpenter, 1993] TFS [Zajac, 1992] and CUF [Dorre and Dorna, 1993] which augment feature logic with a type system. One such expressive device employed both within LFG [Kaplan and Bresnan, 1982] and HPSG but is unavailable in feature logic is that of set descriptions. Although various researchers have studied set descriptions (with ....

R'emi Zajac. Inheritance and ConstraintBased Grammar Formalisms. Computational Linguistics,

....power of the first unification based formalisms with different forms of disjunctive descriptions. Later, other operations came into play, e.g. classical) negation. However the most important extension to formalisms consists of the incorporation of types, for instance in modern systems like TFS [ Zajac, 1992 ] CUF [ Dorre and Dorna, 1993 ] or TDL [ Krieger and Schafer, 1994 ] Types are ordered hierarchically as it is known from object oriented programming languages, a feature heavily employed in lexicalized grammar theories like Head Driven Phrase Structure Grammar (HPSG) Pollard and Sag, ....

....1993 ] in order to make the connection to the implementation clear and to come close to the structured attribute value matrix notation. of feature structures is actually done) nor are we interested in the logic of types, e.g. whether the existence of a greatest lower bound is obligatory (TFS [ Zajac, 1992 ] ALE [ Carpenter and Penn, 1994 ] or optional as in TDL [ Krieger and Schafer, 1994 ] We assume here that typed unification is simply a black box and can be accessed through an interface function (say unify tfs) From this perspective, our expansion mechanism can be either used as a ....

[Article contains additional citation context not shown here]

R'emi Zajac. Inheritance and constraint-based grammar formalisms. Computational Linguistics, 18(2):159--182, 1992.

....( 8] They can represent lexical items, phrases and rules. Usually, no mechanism for manipulating TFSs (e.g. parsing algorithm) is inherent to the formalism. Current approaches to processing HPSG grammars either translate them to Prolog (e.g. 2, 5, 6] or use a general constraint system ([16]) In this paper we provide for parsing with grammars expressed in a general TFS based formalism, a restriction of ALE ( 2] Our motivation is the design of an abstract (WAM like) machine for the formalism ( 14] we consider parsing as a computational process and use it as an operational ....

R'emi Zajac. Inheritance and constraint-based grammar formalisms. Computational Linguistics,

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Rmi Zajac. 1992. "Inheritance and Constraint-based Grammar Formalisms". Computational Linguistics 18 (2), June 1992. pp159-182.

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Rmi Zajac. 1992. "Inheritance and Constraint-Based Grammar Formalisms". Computational Linguistics 18/2, Special Issue on Inheritance, June 1992.

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Zajac, R. (1992). Inheritance and Constraint-Based Grammar Formalisms. Association for Computation Linguistics.

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Zajac, R'emi (1992): "Inheritance and Constraint-Based Grammar Formalisms".

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