Intercausal Reasoning with Uninstantiated Ancestor Nodes

Authors:

Marek J. Druzdzel
Carnegie Mellon University
Department of Engineering and Public Policy
(currently with:
University of Pittsburgh
Department of Information Science
and Intelligent Systems Program
e-mail: marek@sis.pitt.edu)

Max Henrion
Rockwell International Science Center
Palo Alto Laboratory
email: henrion@camis.stanford.edu
(currently with:
Lumina Decision Systems)

Abstract:

Intercausal reasoning is a common inference pattern involving probabilistic dependence of causes of an observed common effect. The sign of this dependence is captured by a qualitative property called product synergy. The current definition of product synergy is insufficient for intercausal reasoning where there are additional uninstantiated causes of the common effect. We propose a new definition of product synergy and prove its adequacy for intercausal reasoning with direct and indirect evidence for the common effect. The new definition is based on a new property matrix half positive semi-definiteness, a weakened form of matrix positive semi-definiteness.