Exact expression for information distance
IEEE Transactions on Information Theory , Volume 63 - Issue 8 p. 4725- 4728
Information distance can be defined not only between two strings but also in a finite multiset of strings of cardinality greater than two. We determine a best upper bound on the information distance. It is exact, since the upper bound on the information distance for all multisets is the same as the lower bound for infinitely many multisets of each of infinitely many cardinalities, up to a constant additive term.