**
John McCarthy
Computer Science Department
Stanford University
Stanford, CA 94305
jmc@cs.stanford.edu
http://www-formal.stanford.edu/jmc/**

**1982**

It is attractive to regard an algorithm as composed of the logic determining what the results are and the control determining how the result is obtained. Logic programmers like to regard programming as controlled deduction, and there have been several proposals for controlling the deduction expressed by a Prolog program and not always using Prolog's normal backtracking algorithm. The present note discusses a map coloring program proposed by Pereira and Porto and two coloring algorithms that can be regarded as control applied to its logic. However, the control mechanisms required go far beyond those that have been contemplated in the Prolog literature.

Robert Kowalski (1979) enunciated the doctrine expressed by the formula

- ALGORITHM = LOGIC + CONTROL
- THE PEREIRA-PORTO LOGIC PROGRAM
- REDUCING THE MAP
- KEMPE TRANSFORMATIONS
- REALIZING THE REDUCTION ALGORITHM BY CONTROL OF THE PEREIRA-PORTO LOGIC
- REALIZING THE KEMPE TRANSFORMATION ALGORITHM
- Acknowledgements
- References
- About this document ...

Sat Feb 22 18:04:49 PDT 1997