To add another one: Lucene uses a finite state transducer to represent a part of its term index: http://blog.mikemccandless.com/2010/12/using-finite-state-trans

To add another one: Lucene uses a finite state transducer to represent a part of its term index: http://blog.mikemccandless.com/2010/12/using-finite-state-transducers-in.html http://blog.mikemccandless.com/2010/12/using-finite-state-tr... --- It's essentially a dictionary as you say, but instead of a direct NLP use case, it might map a word to some numerical value (like a file offset where the term's postings list resides). I actually haven't been able to find anyone else using transducers for this purpose (sans OpenSextant, I think), but I'd be curious to hear about it if others knew. It seems like a really awesome way to represent nearly arbitrary maps/sets of billions of strings.