---
title: "Using Active Connection Graphs for Reasoning with Recursive Rules"
authors:
  - "Donald P. McKay"
  - "Stuart C. Shapiro"
doi: ""
url: "https://ijcai.org/proceedings/1981/72"
pdf: "https://ijcai.org/proceedings/1981/0072.pdf"
venue: "Proceedings of the Seventh International Joint Conference on Artificial Intelligence"
year: 1981
pages: "368-373"
track: "INFERENCE and REASONING"
keywords:
---

# Using Active Connection Graphs for Reasoning with Recursive Rules

Donald P. McKay, Stuart C. Shapiro

*Proceedings of the Seventh International Joint Conference on Artificial Intelligence*, pages 368-373.

## Abstract

Recursive rules, such as "Your parents' ancestors are your ancestors", although very useful for theorem proving, natural language understanding, question-answering and information retrieval systems, present problems for many such systems, either causing infinite loops or requiring that arbitrarily many copies of them be made. SNIP, the SNePS Inference Package, can use recursive rules without either of these problems. A recursive rule causes a cycle to be built in an active connection &raph. Each pass of data through the cycle results in another answer. Cycling stops as soon as either the desired answer is produced, no more answers can be produced or resource bounds are exceeded.