DRIFT: Decompose, Retrieve, Illustrate, then Formalize Theorems
Meiru Zhang, Philipp Borchert, Milan Gritta, Gerasimos Lampouras
TL;DR
DRIFT presents a four-stage framework—Decompose, Retrieve, Illustrate, then Formalize—to tackle the two core challenges in autoformalization: the complexity of informal statements and the lack of contextual usage for retrieved premises. By breaking statements into atomic sub-queries, retrieving precise dependencies, and supplying exemplar theorems to demonstrate usage, DRIFT substantially enhances dependency retrieval and formalization accuracy across in-distribution and out-of-distribution benchmarks. The approach is model-agnostic and consistently outperforms zero-shot and prior retrieval baselines, with particularly strong gains on ConNF and notable improvements on ProofNet. These findings highlight the importance of structured query decomposition and demonstrative context in bridging informal mathematics and formal libraries like Mathlib, and suggest adaptive retrieval strategies to align with model capabilities.
Abstract
Automating the formalization of mathematical statements for theorem proving remains a major challenge for Large Language Models (LLMs). LLMs struggle to identify and utilize the prerequisite mathematical knowledge and its corresponding formal representation in languages like Lean. Current retrieval-augmented autoformalization methods query external libraries using the informal statement directly, but overlook a fundamental limitation: informal mathematical statements are often complex and offer limited context on the underlying math concepts. To address this, we introduce DRIFT, a novel framework that enables LLMs to decompose informal mathematical statements into smaller, more tractable ''sub-components''. This facilitates targeted retrieval of premises from mathematical libraries such as Mathlib. Additionally, DRIFT retrieves illustrative theorems to help models use premises more effectively in formalization tasks. We evaluate DRIFT across diverse benchmarks (ProofNet, ConNF, and MiniF2F-test) and find that it consistently improves premise retrieval, nearly doubling the F1 score compared to the DPR baseline on ProofNet. Notably, DRIFT demonstrates strong performance on the out-of-distribution ConNF benchmark, with BEq+@10 improvements of 37.14% and 42.25% using GPT-4.1 and DeepSeek-V3.1, respectively. Our analysis shows that retrieval effectiveness in mathematical autoformalization depends heavily on model-specific knowledge boundaries, highlighting the need for adaptive retrieval strategies aligned with each model's capabilities.
