---
title: "Short Time Periods"
authors:
  - "Patrick J. Hayes"
  - "James F. Allen"
doi: ""
url: "https://ijcai.org/proceedings/1987/201"
pdf: "https://ijcai.org/proceedings/1987/0201.pdf"
venue: "Proceedings of the Tenth International Joint Conference on Artificial Intelligence"
year: 1987
pages: "981-982"
track: "Reasoning"
keywords:
---

# Short Time Periods

Patrick J. Hayes, James F. Allen

*Proceedings of the Tenth International Joint Conference on Artificial Intelligence*, pages 981-982.

## Abstract

Earlier papers ( Allen and Hayes 1985,1986) described a compact axiomatic theory which provided a formal basis for temporal reasoning. This theory makes a sharp distinction between time points and periops of time. We show here, by considering possible models of the theory, that it can be slightly extended to give a better fit to intuition. In particular, the extended theory is preserved under changes of temporal granularity.