Approximate string matching algorithms (ASMA) determine if two strings are the same, “close enough”, or are distinct. Spelling error detection and correction were early applications of these algorithms, and today ASMAs (or similar techniques) are used in natural language understanding applications. Hundreds of papers have been written on the subject (1980 survey, 2001 survey), but this post is focused on the subset of algorithms that were considered commercially viable for the field of co...