Revisiting the Stability of the Ingleton Inequality: A Tropicalization-Free Approach
This study investigates the stability of the Ingleton inequality under approximate conditional independence—specifically, when the conditional mutual information is small but nonzero—and quantifies the extent to which the inequality may be violated. To this end, we introduce a novel analytical framework that avoids tropicalization and dispenses with the intricate machinery of tropical probability spaces, thereby substantially simplifying the stability analysis. Within this framework, we derive explicit error bounds that improve upon existing estimates, resolve an open problem concerning the stability of the sum of two Ingleton expressions, and consequently construct a new family of entropy inequalities that confirm the stability of this sum.