Negation And Focus in Man - Machine Communication

A ske t ch of a programme f o r man-machine communica t i o n as be ing p repared by Prague l i n g u i s t s is p r e s e n t e d , w i t h a c h a r a c t e r i z a t i o n o f the scope o f nega t i on and of the n a t u r e of focus two problems t h a t appeared c r u c i a l w i t h r e s p e c t t o the f o l l o w i n g i saues i ( i ) g rammat ica l a n a l y s i s o f i n p u t t e x t s , y i e l d i n g unambiguous semant ic r e p r e s e n t a t i o n s (SR s ) o f subsequent sen tences , ( i i ) a l g o r i t h m s t r a n s l a t i n g the SR s i n t o a l o g i c a l l a n guage in the fo rm o f wh i ch the i n f o r m a t i o n ga ined f rom the n a t u r a l language i n p u t i s t o b e s t o r e d i n the computer memory, ( i i i ) fo rm o f the SR s , i . e . t he language s e r v i n g , among o the r purposes , as the o u t p u t o f ( i ) and i n p u t o f ( i i ) . I t i s shown e s p e c i a l l y t h a t the l o g i c a l impact o f n a t u r a l language nega t i on can be accounted f o r o n l y i f t he t o p i c / f o c u a dichotomy i s du l y a n a l y z e d . 1 . A programme f o r man-machine communicat ion, u s i n g a f u l l f l e d g e d a n a l y s i s o f n a t u r a l language, i s be ing prepared b y l i n g u i s t s w o r k i n g a t the F a c u l t y o f Mathematics and P h y s i c s , Char les U n i v e r s i t y , Prague. The a l g o r i t h m s t h a t are f o r m u l a t ed are d i v i d e d i n t o the f o l l o w i n g g roups : ( i ) g rammat ica l a n a l y s i s o f i n p u t t e x t s ( i . e . o f Czech t e x t s on e l e c t r o n i c s ) , y i e l d i n g unambiguous semant ic r e p r e s e n t a t i o n s o f subsequent s e n t ences ( i n the fo rm o f l i n e a r i z e d dependency g r a p h s ) ; ( i i ) a l g o r i t h m s t r a n s l a t i n g f rom the semant ic r e p r e s e n t a t i o n s (wh ich s t i l l have a l i n g u i s t i c c h a r a c t e r ) i n t o a l o g i c a l language, w e l l adapted to the purposes o f the t h e o r y o f i n f e r e n c e e t c . ; i n t h i s fo rm the i n f o r m a t i o n ga ined f rom the n a t u r a l language i n p u t i s t o b e s t o r e d i n the compute r memory (and c o n f r o n t e d w i t h f u r t h e r such i n f o r m a t i o n , ga ined l a t e r f rom o t h e r t e x t s ) ; ( i i i ) a l g o r i t h m s l o o k i n g f o r I n f o r m a t i o n needed a c c o r d i n g to ques t i ons f o r m u l a t e d by the users in Czech and ana lyzed acco rd ing to the a l g o r i t h m s o f ( i ) ; ( i v ) a l g o r i t h m s o f the s y n t h e s i s o f answers ( i n Czech). We want to c h a r a c t e r i z e in the present paper the s o l u t i o n o f two problems t h a t appeared c r u c i a l f o r ( i ) and ( i i ) , a s w e l l a s f o r the form o f the semant ic r e p r e s e n t a t i o n s (SR 's) of sentences ( the language s e r v i n g as the ou tpu t o f ( i ) and i n p u t o f ( i i ) , among o t h e r p u r p o s e s ) . 2 . L i n g u i s t i c c o n s i d e r a t i o n s have l e d t o the f o l l o w i n g f o rm of SR's (where every A s tands f o r a l e x i c a l u n i t , accompanied, p o s s i b l y , b y markers o f " m o r p h o l o g i c a l meanings" (grammatemes), such as P l u r a l , P r e t e r i t e , e t c . , the s u b s c r i p t d e n o t i n g t h e f u n c t i o n o f the g i v e n i t e m i n the sen tence : A c t o r , O b j e c t i v e , D a t i v e , P l a c e , D i r e c t i o n , e t c . ) : Each of the p a r t i c i p a n t s , denoted here as A , can , o f cou rse , i t s e l f c o n s i s t i n a group headed by the v e r b , so t h a t a s t r u c t u r e of t he shape (1 ) may be embedded, under c e r t a i n c o n d i t i o n s ( s p e c i f ­ i e d by a g e n e r a t i v e grammar u s i n g dependency s y n t a x ) i n t o ano ther such s t r u c t u r e . The s u p e r s c r i p t b i s a t t ached to those e l e ­ ments t h a t a re c o n t e x t u a l l y bound, i . e . i n c l u d e d i n the t o p i c ; t h e o the rs c o n s t i t u t e the comment o r t h e focus o f t he sen tence . The l e f t t o r i g h t o r d e r ( w i t h t o p i c p reced ing the f ocus ) may be regarded as a "deep" word o r d e r , co r respond ing to the p r imary word o r d e r o f the s u r f a c e l e v e l (combined w i t h a n e u t r a l i n t o n a t i o n ) . W i t h a "hype rsen tence " of t he Ross-Sadock type an 5R can be paraphrased as " I t e l l you about Top i c t h a t F o c u s " , e . g . ( I t e l l you about ) Fa the r ( t h a t he) i s coming. ( I t e l l you