Lexical conceptual structure and event structure template In decomposition semantics, the meaning of words is analyzed into components that

capture generalization on semantic relations. These components may combine to yield the semantics of different words. Such generalization involves capturing entailment relationships, with reference to semantic fields (Gruber 1965) and thematic roles.

Jackendoff (1990) captures these relationships by a set of ontological categories that form the essential units of conceptual structure that do not appear in isolation. They are only observed in combinations built up into conceptual constituents and their existence must be inferred from their effect on language and cognition as a whole (Jackendoff 1990:32). These ontological categories such as EVENT, STATE, ACTION, THING, PLACE, PATH, PROPERTY and AMOUNT consist of functions and arguments of these functions. These functions capture semantic concepts such as motion, causation, spatial location etc. A lexical item consists of an entity with zero or more open arguments.

Conceptual structure exists at a cognitive level and is about what a language expresses but it is not restricted to syntactic terms. It is a central cognitive level of

representation that interacts with other cognitive capacities such as the spatial representation module. Linking between conceptual structure and syntactic structure is achieved by correspondence rules. While all syntactic constituents must correspond to elements in conceptual structure, not all conceptual categories express syntactic constituents. I illustrate the above with (65) below:

(65) Syntactic Structure

[s [NP John [VP ran[PP into [NP [the room]]]]].

Conceptual Structure

[event GO([thing John],[path TO [Place IN ([thing ROOM])]]])].

The sentence correspond to event, the verb the event function GO that has two arguments a thing John corresponding to the first argument and a path , the second argument, corresponding to the PP argument of the verb. Path is composite in nature and has a place argument that in turn takes a thing argument ROOM.

In order to capture generalizations about semantic fields and theta roles, Jackendoff posits three TIERS: action tier, thematic tier and temporal tier. The temporal tier links events and states in the action and thematic tiers.

The action tier consists of conceptual functions such as ACT, AFF (AFFECT) and REACT together with arguments of that function. It is designed to capture Actor-Patient relations.

The thematic tier encodes conceptual roles dealing with motion and location and consists of such conceptual functions as GO, STAY, CS (cause + force), MOVE and INCH. Conceptual field features represented as subscripts on a function distinguishes the paradigms from one another. These features capture the field in which a STATE or EVENT is defined. For example, the conceptual feature GO is represented as GOspatial versus GOposs versus GOident versus GOtemp.

Below in (66b) is the conceptual structure for give a double object verb.

b.

The C-structure above consists of a two-tier representation. The uppermost structure is the thematic tier with the function CS ⁺ representing the successful outcome of the application of force (an undetermined outcome will be represented as CS^u). This function takes two arguments: a thing Harry and an event GO which in turn has two arguments: a thing Book and a path, which in turn is composite in nature with two conceptual functions FROM with a thing Harry argument and TO with a thing SAM argument.

The bottom structure represents the action tier with the function AFF⁺. This function captures Actor-Patient relation, with the first argument, the Actor, and the second argument, the Patient. The notation AFF⁺ captures a positive effect of the event on a participant, typically the beneficiary (AFF ^– represents a negatively affected

participant typically the patient).

The Greek symbol superscript stipulates argument binding between conceptual positions and indicates participant identity. A binding argument is notated with a Greek superscript and its bindee with a Greek letter within the square brackets. The assumption being that the part of meaning that corresponds most directly to syntax is the binder.

Mapping between semantic structures into syntactic arguments is achieved through identification of dominance of arguments and their positioning in the different tiers.

Thematic role are represented as sets of argument positions in Conceptual Structure.

For example, Agent is the first argument of ACT, CS and AFF, Theme is the first

argument of GO, BE, STAY and ORIENT, Goal is the argument of TO while Source in the argument of FROM. Priority is given to the action tier with the first argument linked to the subject position and the second to the object position. The subject and the NP canonically following the verb are the canonical positions for action tier roles.

The assumption is that the arguments on the action tier are linked first before arguments on other tiers. In the absence of arguments on the action tier, the first argument on the thematic tier is linked to subject position and so on. In (66b) above for example, the first argument of AFF⁺ HARRY will be linked to the subject and the second argument SAM to the object.

Unlike in the Lexical Mapping theory where arguments in lexical entries are

stipulated in their Argument Structures, Lexical Conceptual Structure has no level of Argument Structure. Information on which entities are arguments is represented as annotations on Lexical Conceptual Structures called A-marking. This is shown in (66b) above where the category thing HARRY and SAM are annotated (the annotation on optional arguments (if any) are put in parenthesis).

It is often observed (Jackendoff 1990:4) that the conceptual functions of Lexical Conceptual Structure may not be primitives but subject to further decomposition and that there may be infinite regression. He states that it is not possible to determine in advance if the bottom is reached. Further decomposition of elements previously thought to be primitives reveal further layers of generalization and explanation.

The notion lexical decomposition presented by Jackendoff (1983), Levin (1988) and Dowty (1974) forms a base for an analysis of event structure by Pustejovsky (1989b, 1991, 1995, 2005). However to address the issue of minimal regression stated above, rather than posit a fixed set of primitives, he posits a primitive event structure type for a lexical item and generative rules that apply to these templates to derive further event types. Events are represented as complex in nature. They may contain sub-events.

For him, a minimal decomposition of an eventuality (as defined in 1.3.2.1 above) would be in terms of an opposition of terms Q and ¬Q. Both terms in the opposition are predicated of different sub-events. A second criterion for the characterization of a verb’s semantics is the specification of causation. Both transitions and causation are structurally associated with slots in the event template for a word. The Event Structure

a brief illustration using the transition event template for exemplification. The type transition (T) consists of a process (P) and a state (S). The process part encodes the negative part of the opposition while the state part consists of the resultant state which is the positive part of the opposition. LCS¹ is the level of predicate decomposition and LCS is the interpretation of the Event Structure (ES) and LCS¹ (Pustejovsky 2006:40).

A detailed discussion of event semantics is given in chapter 3 section 3.2.2.

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In addition to the Event Structure mentioned above, three other levels of a lexical items meaning representation are: Argument Structure, Qualia Structure and Inheritance Structure. Summarizing briefly, Argument Structure is the predicate structure for a word specifying its function and how it maps it to syntactic

expressions. Qualia Structure is the essential attributes of an object as defined by the lexical item. Lastly, Inheritance Structure is how a word is globally related to other concepts.

In this thesis, I do not discuss Argument Structure, Qualia Structure and Inheritance Structure as proposed by Pustejovsky. I discuss only Event Structure and how it may be incorporated within the type relation constraining the mrs value of the CONT feature of a sign in an HPSG system. A type eventstruc-rel that inherits from the type event-rel with seven subtypes process-eventstruc-rel, state-eventstruc-rel, cause-eventstruc-rel, result-eventstruc-rel ,achievement-eventstruc, transition-inchoative-eventstruc-rel and transition-cause-eventstruc-rel captures descriptions present within the Event Structure template posited by Pustejovsky. The type

T

ES P S

LCS¹: [act (j, the-door) &¬closed (the door)

[closed the door]

LCS: cause ([act (j, the-door),become ([closed (the-door)])])

cause-eventstruc-rel has three sub-types that inherit from it; transition-cause-canonical-eventstruc-rel, transition-cause-selfagentive-eventstruc-rel and the transition-cause-ballistic-eventstruc-rel. I discuss further Event Structure semantics in Chapters 3, 6 and 7.