Hello, I am looking for even a simple implementation with at least the following operations: insert/add, remove, mem/contains and at_rank. The at_rank is especially important since it is inefficient to implement it using fold in a set like the ones from the stdlib. Thanks a lot, F.--Caml-list mailing list. Subscription management and archives: https://sympa.inria.fr/sympa/arc/caml-list Beginner's list: http://groups.yahoo.com/group/ocaml_beginners Bug reports: http://caml.inria.fr/bin/caml-bugs