JP2003281132A - System and method of processing natural language, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more accurately analyze the syntactic meaning of a sentence with an omitted constituent which is primarily considered essential such as a subject or object in a Japanese sentence. <P>SOLUTION: When words follow the predicate in a sentence, a speech part category AUX corresponding to the predicate which should not have a case frame is defined. When these words follow the predicate in the sentence, the case frame is deleted. When a phrase connector such that the predicate of the phrase just before it shows a tendency not to receive a noun phrase including 'ha' or 'ga' (in Japanese) appearing at the head of the sentence is present in the sentence, a noun phrase including 'ga' is inserted into the case frame corresponding to the subject of the predicate of the phrase just after the phrase connector if the noun phrase including 'ga' is present at the head of the sentence. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a natural language processing system and a natural language processing method for mathematically handling a natural language used by humans for daily communication.
The present invention also relates to a computer program, and more particularly to a natural language processing system and a natural language processing method for performing syntactic and semantic analysis of Japanese syntax, and a computer program.

More specifically, the present invention is a natural language processing system and a natural language processing system for more accurately performing syntactic and semantic analysis of a sentence such as a Japanese sentence that is originally indispensable, such as a subject and an object, but whose constituent elements are omitted. The present invention relates to a language processing method and a computer program, and more particularly, to a natural language processing system and a natural language processing method and a computer program which highly accurately output information of a subject or object omitted from a sentence, that is, a zero pronoun.

[0003]

2. Description of the Related Art Words used by humans for daily communication such as Japanese and English are called "natural language". Many natural languages have a naturally occurring origin and have evolved with the history of humanity, ethnicity, and society. Of course, a person can communicate by gesturing or gesturing, but natural language can realize the most natural and advanced communication.

On the other hand, with the development of information technology, computers have become established in human society and have been deeply permeated in various industries and daily lives. Now, not only computer data but almost all information contents such as images and sounds are handled on the computer, and it is possible to perform advanced processing such as editing / processing, storage, management, transmission and sharing of information. .

Natural language has an abstract and ambiguous nature by nature, but by treating sentences mathematically,
Computer processing can be performed. As a result, various applications related to natural language such as machine translation, dialogue system, search system, etc.
The service is realized.

Natural language processing is generally divided into processing phases of morphological analysis, syntactic analysis, semantic analysis, and context analysis.

In the morphological analysis, a sentence is segmented into morphemes, which are the smallest semantic units, and a part-of-speech recognition process is performed. In the syntactic analysis, a sentence structure such as a phrase structure is analyzed based on grammatical rules. Since the grammar rules have a tree structure,
The syntactic analysis result generally has a tree structure in which individual morphemes are joined based on the dependency relationship. In the semantic analysis, based on the meaning (concept) of the words in the sentence and the semantic relationship between the words, the semantic structure expressing the meaning conveyed by the sentence is obtained, and the semantic structures are synthesized. In context analysis, a sentence (discourse), which is a series of sentences, is regarded as a basic unit of analysis, and a discourse structure is constructed by obtaining a semantic unity between sentences.

In the syntactic and semantic analysis, the relation between the verb and the other constituent elements in the sentence such as the subject (ie, the case frame of the predicate) is described for the structural sentence after the dependency relation is obtained by the syntactic analysis or the like. It is performed that the semantic relation between the predicate and the related words is extracted using the valence index dictionary.

[0009]

[Problems to be Solved by the Invention] In Japanese sentences, what is considered to be an essential constituent element such as a subject or an object is often omitted. Such abbreviated subjects and objects are called "zero pronouns".

Identifying the substance of the zero pronoun from the context is an essential process for realizing various natural language processing applications such as a dialogue system. Examples of algorithms for identifying the substance of the zero pronoun include MAWalker, AK Joshi and E.
F. Prince co-authored "Centering Theory in Discourse", C
The "Centering theory", which is described in detail in larendon Press, Oxford (1994), can be mentioned.

However, whichever method is used to specify the substance of such a zero pronoun, it is necessary to identify, as a preprocessing, which constituent element is omitted in the sentence.

For example, the case position of the predicate can be specified by using the case frame of the predicate as basic information. The case frame shows what constituent elements can be combined for each predicate, and is also called a valence, and is stored in the valence dictionary.

FIG. 1 shows a case frame with limited selection of the verb "fit" described in the IPAL verb dictionary developed at the Information Technology Promotion Agency Technical Center (IPA). As shown in the figure, a case frame is described for the verb "fit" when only the subject ("ga case") is taken or when the subject and the two cases are taken at the same time. Hum (human: human) and phe (phenomenon: phenomenon), which are given as selection restrictions in Fig. 1, indicate the conceptual category of the noun that takes the case, and the semantic feature (se
mantic feature) or semantic marker
Called. The basic information for identifying the appearance position of the zero pronoun is called the case frame of the predicate.

Now, let us consider a method of searching for an appearance position of a zero pronoun using case frame information.
By referring to the case frame of the predicate, it is possible to easily specify the appearance position of the subject or predicate that may be omitted in the sentence.

For example, in the following sentence (1), a part that may be a zero pronoun is searched for based on the case frame, and "NULL" is used as a symbol corresponding to the zero pronoun.
Insert. As a result, the original sentence has the form shown in (2), but it is clear that the zero pronouns that are not originally necessary are included in the analysis result.

(1) I did not think about it, but it is probably incorrect. (2) Think of (NULL) (NULL) (NULL) (NULL)
It was (null) and not (null), but probably (null) is not correct (null).

The object of the present invention is to solve the above technical problems, and more accurately translates a sentence in which constituent elements are omitted, such as a Japanese sentence, which is originally considered essential such as a subject and an object. Can perform syntactic and semantic analysis,
An object is to provide an excellent natural language processing system, natural language processing method, and computer program.

A further object of the present invention is to provide an excellent natural language processing system, natural language processing method, and computer program capable of accurately outputting information of a subject or object omitted from a sentence, that is, a zero pronoun. To provide.

[0019]

The present invention has been made in consideration of the above problems. The first aspect of the present invention is to perform syntactic and semantic analysis on sentences in which essential constituent elements are omitted. A natural language processing system or a natural language processing method, wherein a part-of-speech category defining means or step for defining a part-of-speech category AUX corresponding to a predicate that should not have a case frame when following the predicate, and another predicate in the input sentence Immediately after or a predicate search or step for searching for a predicate belonging to the part-of-speech category AUX that exists after a certain particle, and a case frame deletion for deleting the case frame of the predicate extracted by the predescription word search or step, or A natural language processing system or a natural language processing method, comprising:

Further, the natural language processing system or the natural language processing method according to the first aspect of the present invention does not receive a noun phrase accompanied by "ha" or "ga" in which the predicate of the immediately preceding phrase appears at the beginning of a sentence. In response to the first phrase connector searching means or step for searching the first phrase connector showing a tendency in the sentence and the fact that the first phrase connector is found in the sentence, "ga" is added to the beginning of the sentence. If there is a accompanying noun phrase, insert the noun phrase in the case frame corresponding to the subject of the predicate of the phrase immediately after the first phrase connector, and / or
If there is a noun phrase accompanied by "ha" at the beginning of the sentence, a first case frame processing means or step for inserting the noun phrase in the case frame corresponding to the predicate of the phrase immediately after the first phrase connector. It may be further equipped.

Further, the natural language processing system or the natural language processing method according to the first aspect of the present invention shows that the predicate of the immediately preceding phrase tends not to receive a noun phrase accompanied by "ha" appearing at the beginning of a sentence. A second phrase connector searching means or step for searching the second phrase connector in the sentence, and a noun phrase accompanied by "ha" at the beginning of the sentence in response to the second phrase connector being found in the sentence. If there is, a second case frame processing means or step for inserting the noun phrase into the case frame corresponding to the predicate of the phrase immediately after the second phrase connector may be further provided.

According to the natural language processing system or the natural language processing method of the first aspect of the present invention, focusing on the auxiliary predicate and the phrase connector, unnecessary case frames are deleted, and the case structure is ambiguous. You can reduce your sex.

Therefore, after that, a usual semantic analysis (case structure analysis) is performed to search for a part that may be zero pronoun based on the case frame, and "NULL" is used as a symbol corresponding to the zero pronoun. By the process of inserting, the appearance position of the zero pronoun can be specified more accurately.

The second aspect of the present invention is described in a computer-readable format so that a natural language process for performing syntactic / semantic analysis of a sentence in which essential components are omitted is executed on a computer system. A part-of-speech category defining step that defines a part-of-speech category AUX corresponding to a predicate that should not have a case frame when it is a computer program and that follows a predicate, and immediately after another predicate or a fixed particle in the input sentence. And a case frame deletion step of deleting a case frame of the predicate extracted by the predescriptor word search step. It is a computer program.

A computer according to the second aspect of the present invention
The program defines a computer program written in a computer-readable format so as to realize a predetermined process on a computer system. In other words, by installing the computer program according to the second aspect of the present invention in the computer system, a cooperative action is exerted on the computer system, and the natural language according to the first aspect of the present invention. It is possible to obtain the same operational effect as the processing device or the natural language processing method.

Further objects, features and advantages of the present invention are as follows.
It will be apparent from the embodiments of the present invention described later and the more detailed description based on the accompanying drawings.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings.

Natural language syntax analysis methods can be roughly classified into methods based on statistical processing and methods based on grammar rule description. The present invention can exert a remarkable effect particularly when applied to syntactic / semantic analysis based on grammar rule description.

The natural language processing system according to the present invention can be implemented, for example, by incorporating it into the syntactic / semantic analysis processing based on the LFG (Lexical-Functional Grammar) grammar theory. In LFG, the linguistic knowledge, or grammar, of native speakers is organized as a component separate from computer processing and other non-grammatical processing parameters that affect the processing behavior of the computer. First, an overview of the natural language processing system will be briefly described. Although the present embodiment is described based on the LFG grammar theory, the present invention can be similarly applied to an analysis system having other grammar rules.

FIG. 2 schematically shows the structure of the natural language processing system 1 based on LFG.

The morpheme analysis unit 2 has a morpheme rule 2A and a morpheme dictionary 2B relating to a specific language such as Japanese, and divides an input sentence into morphemes, which are the smallest semantic units, to perform a part of speech recognition process. For example, if the sentence "My daughter speaks English." Is entered, the result of morphological analysis is "I {Noun} {up} daughter {Noun} is {up} English {Noun}.
{Up} speak {Verb1} {tr} and {jp}. {pt} "is output.

The result of such morphological analysis is then input to the syntactic / semantic analysis unit 3. The syntactic and semantic analysis department
It has dictionaries such as grammar rules 3A and valence valence dictionary 3B, and analyzes the phrase structure based on grammar rules and expresses the meaning conveyed by the sentence based on the meaning of words in the sentence and the meaning relation between words. Analyze the semantic structure (The valence dictionary describes the relationship between verbs and other constituent elements in the sentence, such as the subject, and can extract the semantic relationship between predicates and related words).

Then, as a result of the syntactic analysis, "c-structure (constituent structur) which represents a phrase structure of a sentence composed of words and morphemes as a tree structure.
e) ", and as a result of semantically and functionally analyzing the input sentence based on the case structure of the subject, object, etc., such as question sentence, past tense, polite sentence," f-structure (functional stru
cture) "is output.

In FIGS. 3 and 4, the c-structure and f-st obtained as a result of processing the input sentence "My daughter speaks English" by the syntactic / semantic analysis unit 1.
In each of the figures, the figures are shown.

The c-structure is a tree structure representing the structure of words and phrases in a sentence, and is defined by the syntax category. For example, a phonological interpretation for generating a phoneme string can be performed based on c-structure. On the other hand, f-structure is
It is a clear expression of grammatical functions and is composed of grammatical function names, semantic forms, and feature symbols. By referring to f-structure, the subject, the object, and the complement
t) and modifiers (adjunct) can be understood. f-structure is c-structure
It is a set of features attached to each node of ure, and is expressed in the form of an attribute-attribute value matrix as shown in FIG. In other words, the left side in [] is the feature (attribute)
And the right side is the feature value (attribute value).

For details of LFG, see, for example, R.
Paper "Lexical-Functio" co-authored by M. Kaplan and J. Bresnan
nal Grammar: A Formal System for Grammatical Repre
sentation "(The MIT Press, Cambridge (1982). Repr
inted in Formal Issues in Lexical-Functional Gramma
r, pp. 29-130.CSLI publications, Stanford Univers
ity (1995).).

In the Japanese sentence, what is considered to be an essential constituent element such as a subject and an object is often omitted. In order to perform more accurate context analysis, it is indispensable to identify such zero pronoun entities. Therefore, as a preprocessing thereof, it is necessary for the syntactic / semantic analysis unit 3 to identify which constituent element is omitted in the sentence.

Therefore, in the present invention, first, a part-of-speech category AUX corresponding to "a predicate that should not have a case frame when it follows a predicate" is defined. For example, “see,” “is,” “is not,” and the like included in the sentence example (1) described above are words that belong to the AUX category. If these words follow the predicate, they have no case frame.

Further, when specifying the appearance position of the zero pronoun, the processing when two or more phrases are combined becomes a particular problem. In this case, the particle "ha" or the case particle "ga" is added at the beginning of the sentence.
It becomes a problem to identify which predicate of the noun phrase that appears with "."

On the other hand, in the present invention, attention is paid to a phrase connector that connects phrases. The phrase connector is "ga""kara"
Conjunctive particles such as "shi", conjunctions, "nara" and "tarara"
It can be categorized into such things as "condition", "monono" such as "mono" and "koroga", and special nouns such as "time" and "koro". In the present invention, these phrase connectors (or combinations thereof) are reclassified in terms of subordinate phrase structure. For example, phrase connectors are classified into the following three types.

Phrase connecter A: A phrase connecter showing a tendency that the predicate of the immediately preceding phrase does not receive a noun phrase accompanied by "ha" and "ga" appearing at the beginning of a sentence. "Tsutsu" and "repetitive verbs" are classified here.

Phrase connecter B: A phrase connecter showing a tendency that the predicate of the immediately preceding phrase does not receive a noun phrase accompanied by "ha" appearing at the beginning of a sentence. “No”, “without”, “tara (conditional)”, “even”, etc. are classified here.

Phrase connector C: A phrase connector other than the above. A phrase connector in which the predicate of the immediately preceding phrase can receive a noun phrase accompanied by "ha" or "ga" appearing at the beginning of a sentence.

The classification of these phrase connectors is described in detail, for example, in "Contour of Contemporary Japanese Grammar" by Fujio Minami (Daishukan Shoten, 1993).

FIG. 5 is a flowchart showing the processing procedure of the zero pronoun analysis according to the embodiment of the present invention. Hereinafter, the analysis process of the zero pronoun will be described in detail with reference to this flowchart.

First, a syntax analysis process is executed on the input sentence (step S1).

Whether the predicate belonging to the above-mentioned part-of-speech category AUX exists immediately after another predicate (or after a certain particle is inserted) based on, for example, the parse tree described in the f-structure format. It is judged (step S2).

If such a predicate exists, the case frame of the predicate belonging to this part-of-speech category AUX is deleted as unnecessary (step S3).

Then, it is judged whether or not the above-mentioned connector A exists in the input sentence (step S4). And
When the connector A exists, the following processes I and II are executed (step S5).

Process 1: If there is a noun phrase accompanied by "ga" at the beginning of the sentence, the noun phrase is inserted into the case frame corresponding to the subject of the predicate of the phrase immediately after the connector A.

Similarly, it is judged whether or not the above-mentioned connector is present in the input sentence (step S6), and if the connector B is present, the following processing II is executed (step S).
8).

Process 2: If there is a noun phrase accompanied by "ha" at the beginning of the sentence, the noun phrase is inserted into the case frame corresponding to the predicate of the phrase immediately after the connector A or B. However, when there are a plurality of case frames, the ambiguity is left and the ambiguity is resolved in the subsequent semantic analysis.

By the above processing, unnecessary case frames can be deleted from the syntactic parse tree to reduce the ambiguity of the case structure. Therefore, a normal semantic analysis (case structure analysis) (step S8) is performed to eliminate the zero pronoun. The appearance position of can be specified more accurately.

FIG. 6 shows the result of parsing the sentence example "I found out by reading his book."

Further, FIG. 7 shows the result of applying the semantic analysis (case structure analysis) to the syntax analysis tree shown in FIG. In the figure, the zero pronoun is "NUL
It is described by "L". As can be seen from the figure, NULL is added to an appropriate position of the parse tree. The correct result is obtained as a zero pronoun analysis of a single sentence. Therefore, according to the result of analyzing the sentence example "I read and found his book" by this method, "I read his book and di
You can get the correct translation result with "scovered something."

[Supplement] The present invention has been described in detail with reference to the specific embodiments. However, it is obvious that those skilled in the art can modify or substitute the embodiments without departing from the scope of the present invention. That is, the present invention has been disclosed in the form of exemplification, and the contents of this specification should not be construed in a limited manner. In order to determine the gist of the present invention, the section of the claims described at the beginning should be taken into consideration.

[0057]

As described above in detail, according to the present invention,
An excellent natural language processing system and natural language processing method capable of more accurately performing syntactic and semantic analysis on a sentence such as a Japanese sentence that is originally indispensable, such as a subject or an object, but whose constituent elements are omitted, and A computer program can be provided.

Further, according to the present invention, an excellent natural language processing system and natural language processing method capable of accurately outputting information of a subject or object omitted from a sentence, that is, a zero pronoun, and a computer, A program can be provided.

The present invention is characterized by reducing unnecessary case frames and reducing the ambiguity of the case structure by paying attention to auxiliary predicates and phrase connectors, which enables highly accurate analysis of zero pronouns. Can be done.

[Brief description of drawings]

[Fig. 1] Information Technology Promotion Agency Technical Center (IPA)
It is a figure which showed the case frame with selection restrictions of the verb "fit" described in the IPAL verb dictionary developed by.

FIG. 2 is a diagram schematically showing a configuration of a natural language processing system 1 based on LFG.

[Figure 3] Syntactically the input sentence "My daughter speaks English."
Cs obtained as a result of processing by the semantic analysis unit 1
It is the figure which showed structure.

[Figure 4] Syntactically the input sentence "My daughter speaks English."
Fs obtained as a result of processing by the semantic analysis unit 1
It is the figure which showed structure.

FIG. 5 is a diagram showing a processing procedure of zero pronoun analysis according to an embodiment of the present invention in the form of a flowchart.

FIG. 6 is a diagram showing a sentence parsing result for a sentence example “I have read and found his book.”

FIG. 7 is a diagram showing a result of semantic (case structure) analysis for a sentence example “I found out by reading his book.”

[Explanation of symbols]

1. Natural language processing system 2 ... Morphological analysis unit 2A ... Morphological rules, 2B ... Morphological dictionary 3 ... Syntactic and Semantic Analysis Department 3A ... Grammar rule, 3B ... Bond valence dictionary

Claims (13)

[Claims] 1. A natural language processing system for performing syntactic / semantic analysis of a sentence in which essential components are omitted, wherein a part-of-speech category AUX corresponding to a predicate that should not have a case frame when the predicate follows The part-of-speech category defining means to be defined, the predicate searching means for searching a predicate belonging to the part-of-speech category AUX existing immediately after another predicate in the input sentence or after sandwiching a certain particle, and the predescription word searching means. And a case frame deleting means for deleting the case frame of the predicate. 2. A first phrase connector that searches a sentence for a first phrase connector that tends not to receive a noun phrase with "ha" or "ga" that appears at the beginning of the sentence in the predicate of the immediately preceding phrase. Subject to the search means and the predicate of the phrase immediately following the first phrase connector, if there is a noun phrase with a "ga" at the beginning of the sentence in response to the discovery of the first phrase connector in the sentence. The noun phrase is inserted in the case frame corresponding to, and / or if there is a noun phrase with "ha" at the beginning of the sentence, the noun phrase is inserted in the case frame corresponding to the predicate of the phrase immediately after the first phrase connector. The natural language processing system according to claim 1, further comprising: first case frame processing means for inserting a noun phrase. 3. A second phrase connector searching means for searching a sentence for a second phrase connector showing a tendency that the predicate of the immediately preceding phrase does not receive a noun phrase accompanied by "ha" appearing at the beginning of the sentence. In response to the fact that the second phrase connector is found in the sentence, if there is a noun phrase accompanied by "ha" at the beginning of the sentence, the case frame corresponding to the predicate of the phrase immediately after the second phrase connector is set. The natural language processing system according to claim 1, further comprising second case frame processing means for inserting the noun phrase. 4. A natural language processing system for performing syntactic / semantic analysis of a sentence in which essential components are omitted, wherein a predicate of a preceding phrase appears at the beginning of a sentence with a "ha" or "ga". A phrase connector search means for searching in a sentence for a phrase connector showing a tendency not to receive a phrase, and if a noun phrase accompanied by "ga" at the beginning of the sentence is found in response to the phrase connector being found in the sentence, Insert the noun phrase in the case frame corresponding to the subject of the predicate of the phrase immediately after the phrase connector, and / or if there is a noun phrase with "ha" at the beginning of the sentence, A natural language processing system comprising: a case frame processing means for inserting the noun phrase into a case frame corresponding to a predicate. 5. A natural language processing system that syntactically and semantically analyzes a sentence in which essential components are omitted, and the predicate of the preceding phrase does not receive a noun phrase accompanied by "ha" appearing at the beginning of the sentence. A phrase connector search means for searching a phrase connector showing a tendency in a sentence and a noun phrase accompanied by "ha" at the beginning of the sentence depending on the fact that the phrase connector is found in the sentence. A natural language processing system, comprising: a case frame processing means for inserting the noun phrase into a case frame corresponding to a predicate of a phrase immediately after. 6. A natural language processing method for performing syntactic / semantic analysis of a sentence in which essential components are omitted, wherein a part-of-speech category AUX corresponding to a predicate that should not have a case frame when the predicate follows The part-of-speech category definition step to be defined, the predicate search step of searching for a predicate belonging to the part-of-speech category AUX that exists immediately after another predicate in the input sentence or after a certain particle is sandwiched, and the predescriptor word search step. A case frame deleting step of deleting a case frame of the predicate described above. 7. A first phrase connector that searches for a first phrase connector in a sentence, which shows a tendency that the predicate of the immediately preceding phrase does not receive a noun phrase accompanied by "ha" or "ga" appearing at the beginning of the sentence. Subject of the predicate of the phrase immediately after the first phrase connector, if there is a noun phrase with "ga" at the beginning of the sentence, in response to the search step and the first phrase connector found in the sentence. The noun phrase is inserted in the case frame corresponding to, and / or if there is a noun phrase with "ha" at the beginning of the sentence, the noun phrase is inserted in the case frame corresponding to the predicate of the phrase immediately after the first phrase connector. The natural language processing method according to claim 6, further comprising a first case frame processing step of inserting a noun phrase. 8. A second phrase connector searching step for searching in a sentence for a second phrase connector which shows a tendency that the predicate of the immediately preceding phrase does not receive a noun phrase accompanied by "ha" appearing at the beginning of the sentence. In response to the fact that the second phrase connector is found in the sentence, if there is a noun phrase accompanied by "ha" at the beginning of the sentence, the case frame corresponding to the predicate of the phrase immediately after the second phrase connector is set. 7. The natural language processing method according to claim 6, further comprising a second case frame processing step of inserting the noun phrase. 9. A natural language processing method for syntactic / semantic analysis of a sentence in which essential components are omitted, wherein a predicate of the preceding phrase appears at the beginning of a sentence with a "ha" or "ga". A phrase connector search step of searching for a phrase connector showing a tendency not to receive a phrase in the sentence, and if there is a noun phrase accompanied by “ga” at the beginning of the sentence according to the phrase connector being found in the sentence, Insert the noun phrase in the case frame corresponding to the subject of the predicate of the phrase immediately after the phrase connector, and / or if there is a noun phrase with "ha" at the beginning of the sentence, A case frame processing step of inserting the noun phrase into a case frame corresponding to a predicate, the natural language processing method. 10. A natural language processing method for syntactic / semantic analysis of a sentence in which essential components are omitted, wherein a predicate of a preceding phrase does not receive a noun phrase accompanied by "ha" appearing at the beginning of the sentence. According to the phrase connector search step of searching for a phrase connector showing a tendency in the sentence, and if there is a noun phrase accompanied by “ha” at the beginning of the sentence in response to the phrase connector being found in the sentence, A case frame processing step of inserting the noun phrase into a case frame corresponding to a predicate of a phrase immediately after, the natural language processing method. 11. A computer program written in a computer-readable format so as to execute natural language processing for performing syntactic / semantic analysis on a sentence in which essential components are omitted, in a predicate. A part-of-speech category definition step that defines a part-of-speech category AUX corresponding to a predicate that should not have a case frame when following, and the part-of-speech category AUX that exists immediately after another predicate or after a certain particle in the input sentence. A computer program, comprising: a predicate search step of searching for a predicate belonging to, and a case frame deletion step of deleting the case frame of the predicate extracted by the predescription word search step. 12. A computer program written in a computer-readable format so as to execute a natural language process for performing syntactic / semantic analysis on a sentence in which essential components are omitted, the computer program comprising: A phrase connector search step that searches for a phrase connector that tends to not receive a noun phrase with a "ha" or "ga" appearing at the beginning of the phrase in the sentence, and the phrase connector is found in the sentence. Accordingly, if there is a noun phrase accompanied by "ga" at the beginning of the sentence, the noun phrase is inserted in the case frame corresponding to the subject of the predicate of the phrase immediately after the phrase connector, and / or at the beginning of the sentence. If there is a noun phrase accompanied by "ha", a case frame processing step of inserting the noun phrase into the case frame corresponding to the predicate of the phrase immediately after the phrase connector, the computer program characterized by the above-mentioned. . 13. A computer program written in a computer-readable format so as to execute a natural language process for performing syntactic / semantic analysis on a sentence in which essential components are omitted, the computer program comprising: Depending on the phrase connector search step of searching for a phrase connector in the sentence that indicates that the predicate of the phrase does not receive the noun phrase with "ha" appearing at the beginning of the sentence, and the phrase connector is found in the sentence. And a case frame processing step of inserting the noun phrase into the case frame corresponding to the predicate of the phrase immediately after the phrase connector, if there is a noun phrase accompanied by "ha" at the beginning of the sentence. A computer program that does.