1. What is the 'Levenshtein'?
Levenshtein is the Russian scientist by whom the edit distance calculation was
invented.
Mathematically it is a metric on the space of strings that defines this distance
as minimal number of edit operations necessary to transform one of these two strings
into the other. Edit operations can either be insertions, deletions or substitutions
of characters. This operation obviously is symmetric and fulfills the triangle
inequation.


