We have a spellchecker software. And one of it crucial parts is hypothesis generator which use Levenshtein distance as a measure of distance between words. The problem with Levenshtein distance is that it's not so easy to calculate (from application performance point of view), so we are came up with an idea to use Hamming distance as a fast reject algorithm for candidates.
So I interested in formal proof of the following statement: suppose you have two strings of equal length. Is it right that Levenshtein distance between them is no more that Hamming distance?