Learning Randomized Reductions
Ferhat Erata, Orr Paradise, Thanos Typaldos, Timos Antonopoulos, ThanhVu Nguyen, Shafi Goldwasser, Ruzica Piskac
TL;DR
This work presents Bitween, a learning-based framework for automatically discovering randomized self-reductions (RSRs) of a function $f$ from correlated samples, by formalizing RSRs with query and recovery classes $(Q,P)$ and a PAC-like learning notion under multiple sample-access models. The Vanilla Bitween backend uses regression-based learning to identify RSRs within a fixed query set, outperforming symbolic regression and MILP baselines, while Agentic Bitween leverages large language models to dynamically generate novel query functions and verify properties, achieving richer RSR discovery. The authors introduce RSR-Bench, a benchmark of 80 mathematical and ML-related functions, to evaluate discovery methods under rigorous verification, and demonstrate significant improvements in verifiable RSRs and function coverage. Collectively, the paper provides a rigorous theoretical framework and a scalable automation pipeline for discovering randomized reductions with potential impact on complexity theory and cryptography.
Abstract
A self-corrector for a function $f$ takes a black-box oracle computing $f$ that is correct on most inputs and turns it into one that is correct on every input with high probability. Self-correctors exist for any function that is randomly self-reducible (RSR), where the value $f$ at a given point $x$ can be recovered by computing $f$ on random correlated points. While RSRs enable powerful self-correction capabilities and have applications in complexity theory and cryptography, their discovery has traditionally required manual derivation by experts. We present Bitween, a method and tool for automated learning of randomized self-reductions for mathematical functions. We make two key contributions: First, we demonstrate that our learning framework based on linear regression outperforms sophisticated methods including genetic algorithms, symbolic regression, and mixed-integer linear programming for discovering RSRs from correlated samples. Second, we introduce Agentic Bitween, a neuro-symbolic approach where large language models dynamically discover novel query functions for RSR property discovery, leveraging vanilla Bitween as a tool for inference and verification, moving beyond the fixed query functions ($x+r$, $x-r$, $x \cdot r$, $x$, $r$) previously used in the literature. On RSR-Bench, our benchmark suite of 80 scientific and machine learning functions, vanilla Bitween surpasses existing symbolic methods, while Agentic Bitween discovers new RSR properties using frontier models to uncover query functions.
