.
 
                           
 
                                              .
                                      .
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                                                                                                                       ij :
 
                                                                                                                                      (),
                                                                                                                                     
                                                                                                                                      () - .
                                                                                                                                        - .
 
 
 
 
 
 
 
 
 
 
 
 
       - . ,
                                    .
       - .
      - .
        - .
       - .
      - .
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                                                                                                         
                                                                                                                           
 
                                                                                                                          
 
                                 
                                                                                                                           
                                                                                                                                                                                       2 1992