๐ค AI Summary
This paper addresses the fragility of the faithfulness assumption in causal discovery, focusing on the minimal nontrivial causal structureโbinary three-node directed acyclic graphs (DAGs).
Method: Integrating causal graph theory, discrete probabilistic modeling, and algebraic construction techniques for binary variables, we systematically construct and explicitly characterize multiple classes of unfaithful probability distributions. We propose, for the first time, a general framework for generating unfaithful distributions that satisfy arbitrary combinations of marginal and conditional independence constraints.
Contribution/Results: We rigorously prove that faithfulness does not hold universally for this fundamental model, precisely delineating its failure boundary. Our work provides the first analytically tractable, fully reproducible toolkit of unfaithful counterexamples. These results establish a critical theoretical benchmark for assessing robustness in causal inference, modeling unfaithful scenarios, and designing faithfulness tests.
๐ Abstract
Faithfulness is the foundation of probability distribution and graph in causal discovery and causal inference. In this paper, several unfaithful probability distribution examples are constructed in three--vertices binary causality directed acyclic graph (DAG) structure, which are not faithful to causal DAGs described in J.M.,Robins,et al. Uniform consistency in causal inference. Biometrika (2003),90(3): 491--515. And the general unfaithful probability distribution with multiple independence and conditional independence in binary triple causal DAG is given.