---
title: "Query Evaluation and Progression in AOL Knowledge Bases"
authors:
  - "Gerhard Lakemeyer"
  - "Hector J. Levesque"
doi: ""
url: "https://ijcai.org/proceedings/1999/19"
pdf: "https://ijcai.org/proceedings/1999/0019.pdf"
venue: "Proceedings of the Sixteenth International Joint Conference on Artificial Intelligence"
year: 1999
pages: "124-130"
track: "Automated Reasoning"
keywords:
---

# Query Evaluation and Progression in AOL Knowledge Bases

Gerhard Lakemeyer, Hector J. Levesque

*Proceedings of the Sixteenth International Joint Conference on Artificial Intelligence*, pages 124-130.

## Abstract

Recently Lakemeyer and Levesque proposed the logic AO £, which amalgamates both the situation calculus and Levesque's logic of only knowing. While very expressive the practical relevance of the formalism is unclear because it heavily relies on second-order logic. In this paper we demonstrate that the picture is not as bleak as it may seem. In particular, we show that for large classes of AO £ knowledge bases and queries, including epistemic ones, query evaluation requires first-order reasoning only. We also provide a simple semantic definition of progressing a knowledge base. For a particular class of knowledge bases, adapted from earlier results by Lin and Reiter, we show that progression is first-order representable and easy to compute.