the following is a detailed explanation of the information partitioning apparatus , the information partitioning method and the information partitioning program achieved in the first embodiment of the present invention , given in reference to the drawings . fig1 is a block diagram showing the functional structure of the information partitioning apparatus achieved in the first embodiment . the functions of the information partitioning apparatus in the first embodiment , which may be achieved by , for instance , installing an information partitioning program ( including a data file , a table having stored therein data and the like ) that is recorded in a recording medium such as a cd - rom or a flexible disk into an information processing apparatus having a communication function , e . g ., a computer or by downloading such an information partitioning program from a network and installing the downloaded program in the information processing apparatus , are provided as shown in fig1 . an information partitioning apparatus 100 in the first embodiment shown in fig1 includes a document comparison unit 101 , a comparison result storage unit 102 , a labeling unit 103 , reference source document data 104 , reference source document / label correspondence data 105 and a labeling result storage unit 106 . the document comparison unit 101 compares an input document with a reference source document which is to be described later and detects an edit status indicating an increase / decrease or an alteration manifesting between data in the reference source document and data in the input document and the corresponding data areas ( both in the reference source document and in the input document ). the document comparison unit 101 may be achieved by adopting , for instance , the method disclosed in reference literature “ e . myers , “ an o ( nd ) ( difference algorithm and its variations ”, algorithmica 1 , 2 ( 1986 ), pp . 251 - 266 ”. the edit status indicates the comparison results obtained at the document comparison unit 101 as described above , which are classified as “ match ”, “ alter ”, “ insert ” or “ delete ”. the document comparison unit 101 indicates “ match ” when it detects identical expressions at a given position i in the reference source document and at a given position j in the input document . the document comparison unit 101 indicates “ alter ” when it detects a given area ( a range from a given position i to another position i + n ( n ≧ 0 )) in the reference source document replaced with a given area ( ranging from a given position j to another position j + m ( m ≧ 0 )) in the input document . “ insert ” is indicated when the document comparison unit 101 detects that the input document includes a character string inserted between a given position i and a given position i + 1 in the reference source document . “ delete ” is indicated when the document comparison unit 101 detects that a given area ( ranging from a given position i to another position i + n ( n ≧ 0 )) in the reference source document is deleted from the input document . the comparison result storage unit 102 stores in memory the results of the comparison executed by the document comparison unit 101 . the comparison result storage unit 102 stores in memory data indicating a reference source document edit start position , an input document edit start position and an input document edit end position in correspondence to each detected edit status , as shown in fig2 , for instance . the labeling unit 103 assigns sorting labels to individual areas in the input document by using the data stored in the comparison result storage unit 102 and data contained in the reference source document / label correspondence data 105 , which are to be detailed later . the labeling result storage unit 106 stores in memory the results of the processing ( the labeling results ) executed by the labeling unit 103 . the labeling result data recorded in the labeling result storage unit 106 may be data indicating input document start positions , input document end positions and labels , which are stored separately from the input document , such as those shown in fig3 , or may adopt a mode which allows the data to be directly output , such as the data shown in fig9 to be detailed later . the reference source document data 104 constitute a reference source document ( reference source document data ) input to the document comparison unit 101 . it is to be noted that the term “ reference source document data ” may be used to refer to the data themselves or to the storage area where the data are stored in this specification . the reference source document , which is used to extract portions of the input document to be sorted ( hereafter referred to as document portions ), contains character strings in lines constituting , for instance , break points between document portions in units of individual lines by maintaining the original arrangement of the lines . fig4 shows an example of a reference source document that is intended for use when the input document is a patent specification . the reference source document / label correspondence data 105 indicates positions in the reference source document , edit statuses ascertained as the comparison results and labels , as shown in fig5 , for instance . it is to be noted that in this specification , the term “ reference source document / label correspondence data ” may be used to refer to the data themselves or to the storage area where the data are stored . next , the operation executed ( the information partitioning method adopted ) in the information partitioning apparatus 100 in the first embodiment having the structure described above is explained . it is to be noted that the following explanation is given on a specific example in which the document ( data ) shown in fig6 is input in the information partitioning apparatus 100 having stored in advance the reference source document ( data ) in fig4 and the reference source document / label correspondence data shown in fig5 . it is to be noted that the document may be input through a document input unit ( not shown ) by adopting any input method . for instance , document data downloaded via a network from a provider , either free of charge or for a fee , may be input . alternatively , document data may be read out from a recording medium such as a flexible disk or a cd - rom and the document data thus read out may be input . in addition , a document may be entered through a keyboard or a paper document may be converted to an electronic document through ocr ( optical character reader ) and then may be input . moreover , an e - mail may be directly input or an e - mail taken in from a mail server may be input . in such a case , the main text portion alone may be input by first slicing out the main text portion . the document input through the document input unit is then transferred to the document comparison unit 101 as character string data . the document comparison unit 101 executes a comparison of the input document with the reference source document and detects differences between the two documents . the document comparison unit 101 adopting , for instance , the document comparison method disclosed in the reference literature mentioned above detects the differences between the two documents by extracting in sequence the document data in the reference source document and the input document in units of the individual lines , comparing the individual lines to ascertain whether or not they contain identical character strings and looking for matching lines so as to minimize the number of unmatched lines . fig7 shows the results of the comparison of the reference source document ref shown in fig4 and the input document in shown in fig6 . in fig7 , the numerals on the left side each indicate a specific position , which are provided to facilitate the explanation . it is to be noted that the processing is executed on the reference source document ref and the input document in both containing information used to specify positions ( line positions ) in the documents . namely , if the input document initially does not contain such information , the document comparison unit 101 first executes processing for adding position information . by minimizing the number of lines that are left unmatched , the document comparison unit 101 detects the line at position 2 in the reference source document ref and the line at position 3 ′ in the input document in , the line at position 3 in the reference source document ref and the line at position 10 ′ in the input document in , and the line at position 4 in the reference source document ref and the position 11 ′ in the input document in as sets of matching lines . it is to be noted that the line at position 0 immediately preceding the first line in the reference source document ref and the line at position 0 ′ immediately preceding the first line in the input document in ( a hypothetical combination that does not exist ) and the line at position 5 immediately following the last line in the reference source document ref and the line at position 14 ′ immediately following the last line in the input document in ( a hypothetical combination that does not exist ) are both regarded as sets with matching lines . after detecting the matching lines in the reference source document ref and the input document in as described above , the document comparison unit 101 generates ( data indicating ) the comparison results to be stored into the comparison result storage unit 102 . the comparison result data in fig2 explained earlier are data stored in the comparison result storage unit 102 when the reference source document ref and input document in achieve correspondence as shown in fig6 . it is to be noted that the result data stored in the comparison result storage unit 102 may indicate all the types of edit statuses , i . e ., “ match ”, “ alter ”, “ insert ” and “ delete ”, may indicate three different types of edit statuses , i . e ., “ alter ”, “ insert ” and “ delete ” or may indicate two different types of edit statuses , “ alter ” and “ insert ”. namely , while document portions can be sorted and extracted as long as at least the two edit statuses , i . e ., “ alter ” and “ insert ”, can be recognized , faster processing may be achieved depending upon the specific structure of the comparison result storage unit 102 if “ match ”, “ alter ”, “ insert ” and “ delete ” or “ alter ”, “ insert ” and “ delete ” output from the document comparison unit are directly stored without first sifting the output . fig2 shows result data stored in the comparison result storage unit 102 , which indicate only two types of edit statuses , “ alter ” and “ insert ”. between the two successive matched lines in the reference source document ref , i . e ., between the line at position 0 and the line at position 2 , a line at position 1 is present , whereas there are two lines present between the corresponding pair of matched lines at position 0 ′ and position 3 ′ in the input document in . these two lines do not match the line at position 1 in the reference source document and , accordingly , the edit status “ alter ”, the reference source document edit start position “ 1 ” “ the input document edit start position ” 1 ′” and the input document edit end position “ 2 ′” are stored as the first set of records in the comparison results data . there is no line between the next two matched lines at position 2 and position 3 in the reference source document ref , whereas there are six lines present between the corresponding matched lines in the input document in , i . e ., between the lines at position 3 ′ and the line at position 10 ′. accordingly , the edit status “ insert ”, the reference source document edit start position “ 2 ”, the input document edit start position “ 4 ′” and the input document edit end position “ 9 ′” are stored as the next set of records in the comparison results data . in addition , since there is no line present between the next two matched lines at positions 3 and 4 in the reference source document ref , and also , there is no line present between the corresponding matched lines in the input document in , i . e ., between the line at position 10 ′ and the line at position 11 ′. since the edit status is not either “ insert ” or “ alter ”, the data corresponding to the results of this particular comparison are not stored into the comparison result storage unit 102 . the third set of records in fig2 is generated and stored based upon the same principle as that which applies to the second set of records in fig2 . next , the labeling unit 103 assigns labels by using the reference source document / label correspondence data 105 and the data at the comparison result storage unit 102 . fig8 presents a flowchart of the label assigning operation executed by the labeling unit 103 . the labeling unit 103 extracts a set of the result data ( a set of records ) in the comparison result storage unit 102 ( s 701 ) and makes a decision as to whether or not the edit status in the extracted result data indicate “ alter ” or “ insert ” ( s 702 , s 703 ). if it is judged that the edit status in the extracted result data does not indicate either “ alter ” or “ insert ” ( in other words , if the edit status is “ delete ” or “ match ”), the labeling unit 103 makes a decision as to whether or not there are result data yet to be processed ( s 710 ), and the operation returns to step s 701 to extract another set of result data if it is judged that there are still unprocessed results data , whereas the sequence of processing in fig8 ends if there are no more unprocessed result data remaining . it is to be noted that if the data stored in the comparison result storage unit 102 indicate only two types of statuses “ alter ” and “ insert ”, a decision is made as to whether the edit status indicates “ alter ” or “ insert ”. if the edit status is judged to indicate “ insert ” or “ alter ”, the reference source document start position in the same set of result data is ascertained ( s 704 ). then , by using the combination of the edit status and the reference source document start position as a key , the reference source document / label correspondence data 105 are searched to find the corresponding set of records ( s 705 , s 706 ). in other words , a set of records indicating a position matching the reference source start position and an edit status matching the detected edit status is found in the reference source document / label correspondence data 105 . once the search is executed successfully , the corresponding character string area ( document portion ) in the input document is extracted ( s 707 ) based upon the input document edit start position and the input document edit end position in the results data , ascertains the value ( label ) stored in the label field in the records searched from the reference source document / label correspondence data 105 ( s 708 ), the label thus obtained is attached to the extracted character string area ( document portion ) and the labeled document portion is stored into the labeling result storage unit 106 ( s 709 ). the data stored into the labeling result storage unit 106 may be the type of data such as that shown in fig3 that allows the generation of an output document ( see fig9 ) by using the input document in response to an output requests , or they may be the type of data that can be directly output in response to an output request , as shown in fig9 . it is to be noted that if the data adopt the former mode , processing for extracting the input document edit start position and the input document edit end position in the result data is executed in step s 707 . the processing described above ( in steps s 701 through s 709 ) is repeatedly executed until there are no more comparison result data that can be processed ( s 710 ), and once the comparison result data have all been processed , the sequence of processing in fig8 ends . for instance , if the first set of comparison result data in fig2 indicating the edit status “ alter ” and the reference source document start position “ 1 ” is extracted in step s 701 , the first set of records in the reference source document / label correspondence data 105 in fig5 is judged to be the match through the search , the label “ title ” in the set of records is extracted and the label “ title ” is attached to the portion ( document portion ) present in the range between position 1 ′ and position 2 ′ in the input document . since there are other sets of result data yet to be processed at this point , the second set of result data in fig2 is then extracted . these result data indicate the edit status “ insert ” and the reference source document start position “ 2 ”. thus , it is judged that the second set of records in the reference source document / label correspondence data 105 in fig5 is the match through the search , the label “ claims ” contained in the set of records is extracted and the label “ claims ” is attached to the portion ( document portion ) present in the range between position 4 ′ and position 9 ′ in the input document . since there is another set of result data yet to be processed at this point , the third set of result data in fig2 is then extracted . these result data indicate the edit status “ insert ” and the reference source document start position “ 4 ”. thus , it is judged that the third set of records in the reference source document / label correspondence data 105 in fig5 is the match through the search , the label “ field ” contained in the set of records is extracted and the label “ field ” is attached to the portion ( document portion ) present in the range between position 12 ′ and position 13 ′ in the input document . when data are stored in the labeling result storage unit 106 in the data format shown in fig3 , the output data shown in fig9 may be generated by using the stored data and the input document , as explained below . for instance , based upon the first set of data in fig3 , the character string data from the line 1 ′ through the line 2 ′ in the input document , i . e ., “( title of the invention ) information processing apparatus ” ( the bold parentheses in the figure are replaced with regular parentheses ) are extracted as a document portion and the label “ title ” in the first set of data in fig3 is attached to the extracted document portion . similar processing is executed for the second and third sets of data in fig3 . the group of labeled document portions , such as that shown in fig9 , is output as necessary through a document output unit ( not shown ). for instance , the document output unit may output the labeled document portion group as a screen display , may print it out , may output it by recording it into a recording medium or may output it by transferring it to another apparatus . it is to be noted that no restriction is imposed with regard to the method of output , and the user may be allowed to specify a given label to output the document portion corresponding to the specified label alone , instead of having all the document portions output . as described above , the first embodiment achieves advantages in that a character string area ( document portion ) corresponding to a specific type of information can be recognized and extracted from a processing target document which may not always have a distinct structure in compliance with xml , html or sgml , simply by preparing a reference source document describing superficial characteristics ( character strings or horizontal lines indicating various entries , character strings or horizontal lines present at break points of different entries etc .) that often appear in documents to be sorted . it also achieves an advantage in that by using the labeling data prepared in correspondence to the reference source document , a label can be assigned to a character string area ( document portion ) that has been recognized or extracted . next , the information partitioning apparatus , the information partitioning method and the information partitioning program achieved in the second embodiment of the present invention are described in detail in reference to drawings . fig1 is a block diagram showing the functional structure of an information partitioning apparatus 10 a achieved in the second embodiment , with the same reference numerals assigned to components corresponding to those in fig1 in reference to which the first embodiment has been explained . in addition to the components of the information partitioning apparatus 10 in the first embodiment , the information partitioning apparatus 10 a achieved in the second embodiment includes a reference source document data generation unit 107 and a reference source document / label correspondence data generation unit 108 . since components other than these have functions identical to those in the first embodiment , their explanation is omitted . the reference source document data generation unit 107 generates a reference source document 104 based upon two documents ( document data ) input thereto and stores the generated reference source document in its storage unit . the specific method adopted to generate the reference source document 104 is to be explained later in reference to the operation of the information partitioning apparatus . the reference source document / label correspondence data generation unit 108 generates the reference source document / label correspondence data 105 to be used at the labeling unit 103 and stores the generated reference source document / label correspondence data in its storage unit . the specific method adopted to generate the reference source document / label correspondence data 105 is to be described later in reference to the operation of the information partitioning apparatus . the individual operations executed at the reference source document data generation unit 107 and the reference source document / label correspondence data generation unit 108 differentiate the information partitioning apparatus in the second embodiment from the information partitioning apparatus in the first embodiment , and accordingly , the following explanation focuses on the operations executed at the reference source document data generation unit 107 and the reference source document / label correspondence data generation unit 108 . two different documents ( document data ) having similar superficial characteristics are input to the reference source document data generation unit 107 through a data resource document input unit ( no reference numeral assigned ). for instance , the document shown in fig4 and the document shown in fig1 , both described earlier , may be input . at the reference source document data generation unit 107 , the two documents having been input are first compared with each other . the documents may be compared through a method similar to that adopted in the means for document comparison 101 explained in reference to the first embodiment . if the document comparison execution unit is mainly constituted in software , its processing routine may be used by both the means for document comparison 101 and the reference source document data generation unit 107 . fig1 shows lines in the two documents in 1 and in 2 judged to achieve matches based upon the results of the comparison . the reference source document data generation unit 107 outputs only the lines judged to achieve matches , as shown in fig1 , in the order they appear as a reference source document 104 and stores ( registers ) the output reference source document in its storage unit . fig1 shows the reference source document generated based upon the results of the comparison shown in fig1 . it is to be noted that the reference source document data generation unit 107 excludes blank lines in the two documents in 1 and in 2 in which no characters ( character data ) are present from the match decision - making process . once the processing executed by the reference source document data generation unit 107 is completed , processing by the reference source document / label correspondence data generation unit 108 starts . the reference source document / label correspondence data generation unit 108 works in collaboration with the user to generate the reference source document / label correspondence data . the reference source document / label correspondence data generation unit 108 first correlates portions of the reference source document generated by the reference source document data generation unit 108 to portions of a document ( preferably a document used as a resource when generating the reference source document ) used for the generation of the reference source document / label correspondence data . namely , it recognizes the lines in the resource document corresponding to the specific lines in the reference source document . fig1 shows the correspondence between the reference source document ref in fig1 and one of the documents used as the resource for the generation of the reference source document i . e ., in 1 . it is to be noted that in addition to the corresponding lines shown in fig1 , the reference source document / label correspondence data generation unit 108 regards position 0 preceding position 1 in the reference source document ref and position 0 ′ preceding position 1 ′ in the document in 1 as positions corresponding with each other and regards position 5 following the last position 4 in the reference source document ref and position 14 ′ following the last position 13 ′ in the document in as positions corresponding with each other . next , the reference source document / label correspondence data generation unit 108 recognizes portions with edit statuses that can be judged to indicate “ insert ” or “ alter ” on the premise that the corresponding relationship described above indicates matching lines ( through processing similar to the processing executed by the means for document comparison 101 ), and determines values to indicate the “ reference source document start positions ” and “ edit statuses ” in the reference source document / label correspondence data . at this point , the data do not include any values corresponding to the labels in fig1 . in order to determine the value ( label name ) to indicate the label for the first set of records in fig1 , the reference source document / label correspondence data generation unit 108 brings up a display of the area ( the two lines at positions 1 ′ and 2 ′) corresponding to the edit status “ insert ” in the document in 1 together with a message prompting the user to enter the name of the label to be assigned to this area , and then takes in the value ( label name ) indicating the label name entered by the user in response . the user is also prompted to enter the label values ( label names ) for the second and third sets of records in fig1 . the reference source document / label correspondence data generation unit 108 subsequently outputs the complete reference source document / label correspondence data generated as described above as the reference source document / label correspondence data 105 and stores ( registers ) them in its storage unit . fig1 shows the reference source document / label correspondence data 105 having been generated as described above in the complete form . values indicating the specific label names “ title ” “ claims ” and “ field ” in fig1 are selected and entered by the user . in addition to the advantages of the first embodiment , the second embodiment achieves an advantage in that a reference source document can be automatically generated . once a given reference source document and reference source document / label correspondence data are prepared , a document subsequently input can be sorted by using these data . while two documents are compared with each other by the document comparison unit 101 and the reference source document generation unit 107 in units of individual lines in the embodiments described above , the two documents may instead be compared in units of individual characters , or in units of individual words after executing morphological analysis processing . as a further alternative , the two documents may be compared through a combination of character - based comparison and word - based comparison . in addition , while an input document is first partitioned into document portions and then labels are assigned to the individual document portions in the embodiments explained above , the document partitioning apparatus may simply partition the input document into document portions instead . furthermore , while an explanation is given above on the embodiments in reference to a single reference source document , a plurality of reference source documents of different types such as a reference source document to be used in conjunction with patent specifications , a reference source document to be used in conjunction with patent applications , a reference source document to be used in conjunction with newsletters and a reference source document to be used in conjunction with court rulings may be provided and , in such a case , a plurality of sets of reference source document / label correspondence data should be provided in correspondence . for instance , before inputting the document to be sorted , the user may specify the reference source document to be used to the apparatus , or the input document may be compared with all the reference source documents and then the subsequent processing may be executed by using the reference source document with the greatest number of matching lines as a valid reference source document . alternatively , the reference source document may be automatically selected by ascertaining whether or not a given document contains character strings or character string patterns ( e . g ., a newsletter title ) inherent to a specific type of document ( patent specification , newsletter or court ruling ). while two documents are input to the reference source document generation unit 107 in the second embodiment , three or more different documents may instead be input , and in such a case , the reference source document may be created by including the lines that are commonly present in all the documents , or by including matching lines found in a predetermined number of documents ( e . g ., in the majority of documents ). in addition , while the apparatus automatically determines the “ positions ” and the “ edit statuses ” in the reference source document / label correspondence data and “ labels ” are entered by the user in the second embodiment , reference source document / label correspondence data may be generated by adopting another method . for instance , the “ positions ”, the “ edit statuses ” and the “ labels ” may all be entered by the user or the “ positions ”, the “ edit statuses ” and the “ labels ” may all be automatically determined by the apparatus . the label values may each be constituted with the entire character string in the first line of the document portion corresponding to a given edit status in the resource document or a character string enclosed within parentheses in the first line .