---
title: "Prolog/Ex 1, An Inference Engine Which Explains Both Yes and No Answers"
authors:
  - "Adrian Walker"
doi: ""
url: "https://ijcai.org/proceedings/1983/125"
pdf: "https://ijcai.org/proceedings/1983/0125.pdf"
venue: "Proceedings of the Eighth International Joint Conference on Artificial Intelligence"
year: 1983
pages: "526-527"
track: "Logic Programming"
keywords:
---

# Prolog/Ex 1, An Inference Engine Which Explains Both Yes and No Answers

Adrian Walker

*Proceedings of the Eighth International Joint Conference on Artificial Intelligence*, pages 526-527.

## Abstract

The language Prolog owes much of its in creas ing populari ty t o the fact that one can use it to write knowledge based systems in a declarative style, writing a specificat ion which is also executable . Wh e n a syste m wr itt en in Prolog produces a yes answer t o a ques ti on, it can be m ade to produce an exp l anation of its reasoning However, some reasonable spec ifi catio ns writt e n in Prolog do not produce any answer when executed. Also, when a knowledge base ans wer s no to a question , it does not explain why . This paper describes a ne w inference engine, ca ll ed Prolog / Ex1 . Many programs which do not p r oduce any answer in Prolog do produ ce a n swers in Prol og/ Ex1 . Prolog / Ex1 prov id es exp la nations of both yes and no answers.