1. C H A P T E R N I N E
Logic Programming

2. Attempting to Satisfy the Query talkswith (bob, allen)
Figure 9.1

3. First Attempt to Satisfy the Query talkswith(Who, allen)
Figure 9.2

4. A Partial Family Tree
Figure 9.3

5. A Small Family “Tree”
Figure 9.4

6. Partial Search Tree for append([english, russian], [spanish], L)
Figure 9.5

7. Trace of bsort for the List [5,2,3,1].
Figure 9.6

8. The Factorial Function in Prolog
Figure 9.7

9. Trace of Factorial (4)
Figure 9.8

10. Symbolic Differentiation Rules
Figure 9.9

11. Prolog Symbolic Differentiator
Figure 9.10

12. Search Tree for the Query d(x, 2*x+1, Ans)
Figure 9.11

13. Prolog Solution for the Building Problem
Figure 9.12

14. A Simple BNF Grammar and Parse Tree for “The Giraffe Dreams”†
Figure 9.13

15. Tracing Execution of a Prolog Query
Figure 9.14

16. Prolog DCG for the Syntax of Jay Expressions
Figure 9.15

17. Jay Expression Syntax Extended to Generate Parse Trees
Figure 9.16