Lower Bounds for Monotonic List Labeling

We present optimal lower bound for special cases of the list labeling problem. This problem has diverse practical applications, including implementation of persistent data structures, in the incremental evaluation of computational circuits and in the maintenance of dense sequential files. We prove, under a reasonable restriction on the algorithms, that Ω(n log2n) relabelings are necessary when inserting n items into list monotonically labeled from a label space of size O(n). We also prove that Ω(n log n) relabelings are required in the case of a label space of polynomial size.