I just studied about this 2-4 tree which is a self-balanced tree. Various sources and textbook often mentioned that the insertion, deleting and searching of this tree is $O(\lg n)$.
However, none of them explain the detailed reasons for that run-time complexity. Neither of them also explains them mathematically for the reason behind that run-time complexity.
Therefore, I would like to ask how do i basically show that the run time complexity to process a 2-4 with n keys is $O(\lg n)$?