AR-VLA: True Autoregressive Action Expert for Vision-Language-Action Models. - Yutong Hu 012; Jan-Nico Zaech; Nikolay Nikolov; Yuanqi Yao; Sombit Dey; Giuliano Albanese; Renaud Detry; Luc Van Gool; Danda Pani Paudel (CoRR, 2026)