Results 1 to 2 of 2

Math Help - If A is any set of regular languages, the union of all the elements of A is a regular

  1. #1
    Newbie
    Joined
    Sep 2011
    Posts
    3

    If A is any set of regular languages, the union of all the elements of A is regular

    I am having trouble understanding why this statement is false. The explanation given to us explains that since A could be infinite, that's the reason why the union of all sets can't be guaranteed to be regular. I'm trying to think of an example of a language that isn't regular, such as the language of strings where the number of a's matches the number of b's. Is there a way I could provide a set of regular languages A that could use union to create this language? Any help with understanding why this is the case would be appreciated.
    Last edited by davidp007; September 27th 2011 at 01:50 PM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Oct 2009
    Posts
    5,561
    Thanks
    785

    Re: If A is any set of regular languages, the union of all the elements of A is regul

    Any non-regular language is the countable union of singletons, and each singleton is regular.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. r-regular graph
    Posted in the Discrete Math Forum
    Replies: 1
    Last Post: October 12th 2011, 04:30 PM
  2. Regular Grammar
    Posted in the Discrete Math Forum
    Replies: 2
    Last Post: June 20th 2010, 09:58 AM
  3. regular n-gon
    Posted in the Geometry Forum
    Replies: 1
    Last Post: February 11th 2010, 03:04 AM
  4. Regular Expressions
    Posted in the Discrete Math Forum
    Replies: 0
    Last Post: November 1st 2009, 01:33 AM
  5. Inner and outer regular
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: September 15th 2009, 04:42 AM

Search Tags


/mathhelpforum @mathhelpforum