A Logic Program Schema and Its Applications

In t h i s paper we cons ide r a . spec i f i c type of l o g i c programs ca l led recursive-schema programs and show t h a t the c l ass of r ecu rs i ve -schema programs has s u f f i c i e n t e x p r e s s i v e c a p a b i l i t y , which provides an a l t e r n a t i v e simple proof fo r the resultby Tarnlund concerning the computat ional power of Horn c lause programs. F u r t h e r , i t i s shown t h a t any T u r i n g c o m p u t a b l e l o g i c p rog ram can be e x p r e s s e d as a c o n j u n c t i v e f o r m u l a o f t h r e e recursive-schema programs. Some app l i ca t i on issues are a l so d iscussed in the con tex t s o f program transformat ion and synthes is .