Composition Direction of Seymour's Theorem for Regular Matroids - Formally Verified. - Martin Dvorak; Tristan Figueroa-Reid; Rida Hamadani; Byung-Hak Hwang; Evgenia Karunus; Vladimir Kolmogorov; Alexander Meiburg; Alexander Nelson; Peter Nelson; Mark Sandey; Ivan Sergeev (CoRR, 2025)