|Regular grammar from CFG? email@example.com (Lorin Netsch) (2004-09-03)|
|Re: Regular grammar from CFG? firstname.lastname@example.org (Eric Bodden) (2004-09-07)|
|Re: Regular grammar from CFG? email@example.com (2004-09-07)|
|Re: Regular grammar from CFG? brosgol@worldDOTstd.com (Ben Brosgol) (2004-09-08)|
|Re: Regular grammar from CFG? firstname.lastname@example.org (2004-09-08)|
|Re: Regular grammar from CFG? email@example.com (Friedrich Neurauter) (2004-09-08)|
|Re: Regular grammar from CFG? firstname.lastname@example.org (Carl Cerecke) (2004-09-08)|
|Re: Regular grammar from CFG? email@example.com (2004-09-13)|
|[1 later articles]|
|From:||Eric Bodden <firstname.lastname@example.org>|
|Date:||7 Sep 2004 23:50:39 -0400|
|Organization:||RWTH Aachen University|
|Posted-Date:||07 Sep 2004 23:50:39 EDT|
On 3 Sep 2004 12:42:40 -0400, Lorin Netsch wrote:
> Can anyone tell me how to determine if a given CFG can be represented
> as a regular grammar?
I believe there can be no way to do so, since I think, there is no way
to convert a grammar that is more than regular to one that is regular.
That is due to the Chomsky hierarchy. Type-3 grammars (regular ones)
are strictly weaker then Type-2 and so forth.
Regular grammars allow rules of the types
A -> aB
A -> a
Now just imagine the possible productions of a grammar that is not yet
- A -> B This cannot be represented by a rule of the ones above.
- A -> Ba The same.
... and so forth.
So in my eyes either a grammar is already regular or it is not. And if it
is not it will never be. Please correct me, if I am wrong.
Eric Bodden, ICQ: 12656220, http://www.bodden.de, PGP: BB465582
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