Conditional Probabilistic Bipolar Argumentation Framework: Explanations, Complexity and Approximation

Abstract

Recently, there has been an increasing interest in extending Dung's framework with probability theory, leading to the Probabilistic Argumentation Framework (PAF), and with supports in addition to attacks, leading to the Bipolar Argumentation Framework (BAF). In this paper, we introduce the Conditional Probabilistic Bipolar Argumentation Framework (CPBAF), which extends Probabilistic and Bipolar AF by allowing conditional probabilities on arguments, attacks, and on (possibly cyclic) supports. In this setting, we address the problem of computing the probability that a given argument is accepted. This is carried out by introducing the concept of probabilistic explanation for a given (probabilistic) extension. We show that the complexity of the problem is FP^#P-hard and propose polynomial approximation algorithms with bounded additive error for CPBAF where cycles with an odd number of attacks are forbidden.