π€ AI Summary
Computing exact forward images of neural networks is #P-hard, rendering existing formal verification methods intractable for large-scale networks. To address this, we propose RF-ProVeβa novel framework that reframes forward image approximation as a probabilistic learning problem. RF-ProVe is the first method to integrate random forests, active sampling, and bootstrap randomization for statistically grounded forward image estimation. It provides rigorous statistical guarantees on both input-region purity and global coverage, enabling high-confidence, bounded-error forward image approximations. By synergistically combining ensemble random decision trees, probabilistic approximation, and formal verification, RF-ProVe effectively captures structural patterns in high-dimensional input spaces that satisfy given output constraints. Experimental results demonstrate that RF-ProVe generates compact, formally verifiable forward image approximations even on networks where exact solvers fail, significantly improving both efficiency and scalability of neural network verification.
π Abstract
Although recent provable methods have been developed to compute preimage bounds for neural networks, their scalability is fundamentally limited by the #P-hardness of the problem. In this work, we adopt a novel probabilistic perspective, aiming to deliver solutions with high-confidence guarantees and bounded error. To this end, we investigate the potential of bootstrap-based and randomized approaches that are capable of capturing complex patterns in high-dimensional spaces, including input regions where a given output property holds. In detail, we introduce $ extbf{R}$andom $ extbf{F}$orest $ extbf{Pro}$perty $ extbf{Ve}$rifier ($ exttt{RF-ProVe}$), a method that exploits an ensemble of randomized decision trees to generate candidate input regions satisfying a desired output property and refines them through active resampling. Our theoretical derivations offer formal statistical guarantees on region purity and global coverage, providing a practical, scalable solution for computing compact preimage approximations in cases where exact solvers fail to scale.