---
title: The Dichotomy of Conjunctive Queries on Probabilistic Structures
url: https://www.emergentmind.com/papers/0612102
type: paper
arxiv_id: '0612102'
arxiv_url: https://arxiv.org/abs/0612102
published: '2006-12-20'
categories:
- cs.DB
---

# The Dichotomy of Conjunctive Queries on Probabilistic Structures

## Abstract

We show that for every conjunctive query, the complexity of evaluating it on a probabilistic database is either \PTIME or #\P-complete, and we give an algorithm for deciding whether a given conjunctive query is \PTIME or #\P-complete. The dichotomy property is a fundamental result on query evaluation on probabilistic databases and it gives a complete classification of the complexity of conjunctive queries.