Re: Intersection of regular expression languages

SM Ryan <wyrmwif@tsoft.org>
Sun, 21 Oct 2007 23:58:49 -0000

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Related articles
Intersection of regular expression languages haberg@math.su.se (2007-10-19)
Re: Intersection of regular expression languages neelk@cs.cmu.edu (Neelakantan Krishnaswami) (2007-10-21)
Re: Intersection of regular expression languages cfc@shell01.TheWorld.com (Chris F Clark) (2007-10-21)
Re: Intersection of regular expression languages gene.ressler@gmail.com (Gene) (2007-10-21)
Re: Intersection of regular expression languages wyrmwif@tsoft.org (SM Ryan) (2007-10-21)
Re: Intersection of regular expression languages haberg@math.su.se (2007-10-22)
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From: SM Ryan <wyrmwif@tsoft.org>
Newsgroups: comp.compilers
Date: Sun, 21 Oct 2007 23:58:49 -0000
Organization: Quick STOP Groceries
References: 07-10-063
Keywords: lex, theory
Posted-Date: 22 Oct 2007 00:24:10 EDT

haberg@math.su.se (Hans Aberg) wrote:
# Can the intersection of two regular expression languages be
# constructed as a regular expression language?


Type 3 languages are closed under intersection, so it is possible.
I don't recall offhand, but I think it might just be the intersection
of the state graphs. Convert the REs to DFAs, work with the graphs,
and then you can convert DFAs back to REs.


--
SM Ryan http://www.rawbw.com/~wyrmwif/
Haven't you ever heard the customer is always right?

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