We develop a new finger search tree with worst-case constant update time in the pointer machine (PM) model of computation. This was a major problem in the field of Data Structures and was tantalizingly open for over 20 years, while many attempts by researchers were made to solve it. The result comes as a consequence of the innovative mechanism that guides the rebalancing operations, combined with incremental multiple splitting and fusion techniques over nodes.
Brodal, G. S., Lagogiannis, G., Makris, C., Tsakalidis, A., & Tsichlas, K. (2003). Optimal finger search trees in the pointer machine. Journal of Computer and System Sciences, 67(2), 381–418. https://doi.org/10.1016/S0022-0000(03)00013-8