Inferencing And Search For An Answer In TIBAQ

( i ) The procedure o f i n f e r e n c i n g i s a c t i v a t e d a f t e r the i n p u t s e n t e n c e has been r e c o g n i z e d as a q u e s t i o n . However, i t would be u s e l e s s to s e a r c h t h r o u g h t h e whole d a t a b a s e . Thus o n l y a sma l l p a r t o f t he d a t a base SQ, v i z . t he s e t o f r e p r e s e n t a t i o n s of s e n t e n c e s r e l e v a n t w i t h r e s p e c t t o a g i v e n q u e s t i o n Q, i s a c t i v a t e d , which c o n s i s t s of t hose s e n t e n c e s t h a t c o n t a i n a t l e a s t one t e rm s e m ~ u t i c a l l y e q u i v a l e n t w i t h an e lement a c t u a l l y o c c u r r i n g i n Q, i . e . i n t h e q u e s t i o n t o be answered . Th is s e t i s s e l e c t e d from the d a t a base f o r t h e i n f e r e n c e r u l e s t o o p e r a t e on i t . Let us deno te by Cn(SQ) t h e s e t o f a l l consequences o f SQ. Thus Cn(SQ) i s t h e t h e o r e t i c a l s e t o f s t a t e m e n t s r e l e v a n t f o r t he b u i l d u p of t h e answer . Such a s e t o f consequences would grow beyond any l i m i t s , so t h a t i t i s n e c e s s a r y to f o r m u l a t e a s t r a t e g y which c o n t r o l s t h e whole p r o c e s s . Two d i f f e r e n t s t r a t e g i e s w i l l be d i s c u s s e d .