O(n²) space complexity in ses function?

[PerMildner]

Unless I am mistaken, the Shortest Edit Script function (ses) is not linear in the length of the input. Instead it uses quadratic space for its (mis-named) fp map, in the worst case.

By using the divide-and-conquer idea from Hirschberg, the original Myers algorithm uses linear space both for computing the edit distance D, and for computing the Shortest Edit Script, and this is also what Wu et al. claim is possible with their improved O(NP)-time algorithm.