Candidate-Expanding Routing with Permutation-Stabilized Experts for Mixed-Format Medical VQA

Authors/venue: Hai-Dang Nguyen and Huy-Hieu Pham; arXiv preprint; submitted 1 September 2026 — 72-hour extension. Problem: routing medical visual questions across formats. Contribution: candidate-expanding router and stabilised expert ordering; authors report 92.23% final accuracy across 1,403 retrospective cases. Practical significance: shows how routing and schema controls can improve mixed-format pipelines. Limitations: preprint, internal retrospective analysis, author-reported accuracy is not clinical safety or external validity. Paper