Abstract

Evaluating autoformalized mathematical statements requires determining whether a candidate preserves the mathematical claim intended by a trusted reference. Existing methods approach this problem from complementary directions: reference-free learned evaluators estimate semantic agreement but are not constrained to a formal equivalence relation, while reference-based proof methods typically employ whole-statement logical equivalence to provide formal certificates, which is too coarse for translation fidelity and may identify mathematically unrelated statements.

We introduce Structure-Aware Equivalence (SAE), a role-preserving formal equivalence relation between syntactic and whole-statement logical equivalence that allows formally justified reformulations while preserving translation-relevant mathematical structure. We operationalize SAE in the Autoformalization Correctness Evaluator (ACE), which provides certified equivalence or inequivalence judgments and reports Inconclusive otherwise. On ProofNetVerif, a benchmark introduced with BEq+, ACE retains substantial equivalent-case coverage while remaining highly conservative in certifying disputed or inequivalent pairs. On targeted diagnostics, BEq+ accepts 94-96% of unrelated but whole-statement logically equivalent pairs, while Mathesis LeanScorer accepts 42% of localized meaning-changing perturbations; ACE accepts none of either set as equivalent.

Abstract

Across medical specialties, clinical practice is anchored in evidence-based guidelines that codify best studied diagnostic and treatment pathways. These pathways routinely fall short for the long tail of real-world care not covered by guidelines. Most medical large language models (LLMs), however, are trained to encode common, guideline-focused medical knowledge in their parameters. Current evaluations test models primarily on recalling and reasoning with this memorized content, often in multiple-choice settings. Given the fundamental importance of evidence-based reasoning in medicine, it is neither feasible nor reliable to depend on memorization in practice. To address this gap, we introduce OGCaReBench, a free-form retrieval-focused benchmark aimed at evaluating LLMs at answering clinical questions that require going beyond typical guidelines.

Extracted from published medical case reports and validated by medical experts, OGCaReBench contains long-form clinical questions requiring free-text answers, providing a systematic framework for assessing open-ended medical reasoning in rare, case-based scenarios. Our experiments reveal that even the best-performing baseline (GPT-5.2) correctly answers only 56% of our benchmark with specialized models only reaching 42%. Augmenting models with retrieved medical articles improves this performance to up to 82% (using GPT-5.2) highlighting the importance of evidence-grounding for real-world medical reasoning tasks. This work thus establishes a foundation for benchmarking and advancing both general-purpose and medical LLMs to produce reliable answers in challenging clinical contexts.

Abstract

Leveraging large language models (LLMs) for query expansion has proven highly effective across diverse tasks and languages. Yet, challenges remain in optimizing query formatting and prompting, often with less focus on handling retrieval results.

In this paper, we introduce Multi-query Multi-passage Late Fusion (MMLF), a straightforward yet potent pipeline that generates sub-queries, expands them into pseudo-documents, retrieves them individually, and aggregates results using reciprocal rank fusion.

Our experiments demonstrate that MMLF exhibits superior performance across five BEIR benchmark datasets, achieving an average improvement of 4% and a maximum gain of up to 8% in both Recall@1k and nDCG@10 compared to state of the art across BEIR information retrieval datasets.