Results 1 to 6 of 6

Math Help - subspace

  1. #1
    Super Member
    Joined
    Jun 2009
    From
    Africa
    Posts
    641

    Smile subspace

    hi
    we have \mathbb{E}=\left \{ (x,y)\in \mathbb{R}^{2};xy=0 \right \},i want to know if \mathbb{E} is stable for addition.i also want to know some informations about stability in sets it's new for me.
    thanks.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Banned
    Joined
    Oct 2009
    Posts
    4,261
    Thanks
    2
    Quote Originally Posted by Raoh View Post
    hi
    we have \mathbb{E}=\left \{ (x,y)\in \mathbb{R}^{2};xy=0 \right \},i want to know if \mathbb{E} is stable for addition.i also want to know some informations about stability in sets it's new for me.
    thanks.

    What does being "stable for addition" for a set mean, anyway? Does it mean it is closed wrt addition? If so then it's simple: check what happens with (1,0) and (0,1).

    Tonio
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member
    Joined
    Jun 2009
    From
    Africa
    Posts
    641

    Smile

    well for X=(1,0) and Y=(0,1) elements of \mathbb{E},we have X+Y=(1,1) not element of \mathbb{E},does this equivalent of saying that \mathbb{E} is not stable for addition ?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Banned
    Joined
    Oct 2009
    Posts
    4,261
    Thanks
    2
    Quote Originally Posted by Raoh View Post
    well for X=(1,0) and Y=(0,1) elements of \mathbb{E},we have X+Y=(1,1) not element of \mathbb{E},does this equivalent of saying that \mathbb{E} is not stable for addition ?
    Ok, what part of "what does being stable for addition mean" you didn't understand??
    I DO NOT KNOW what does being stable for addition mean: I said that if it is what ALLLL the rest of the world calls "closed under addition" then...etc.
    Please read carefully my answer.

    Tonio
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor

    Joined
    Apr 2005
    Posts
    16,421
    Thanks
    1856
    Raoh, this is YOUR problem. You used the term "stable under addition" which is not standard (English) so YOU are going to look in your text book or ask your teacher. Tonio asked what "stable under addition" meant and you responded by asking HIM, "Does it mean" and then gave, effectively, what in English would be called "closed under addition". I suspect that is correct, but I am afraid no one here can help you until YOU have checked the definition of "stable under addition".
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Super Member
    Joined
    Jun 2009
    From
    Africa
    Posts
    641

    Smile

    well i translated from the French,anyway thanks for your help(both ).
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Why is this set a subspace ??
    Posted in the Advanced Algebra Forum
    Replies: 2
    Last Post: July 3rd 2010, 10:10 PM
  2. Subspace spanned by subspace
    Posted in the Advanced Algebra Forum
    Replies: 3
    Last Post: February 9th 2010, 08:47 PM
  3. Subspace
    Posted in the Advanced Algebra Forum
    Replies: 4
    Last Post: February 9th 2010, 04:08 AM
  4. How many subspace in F2?
    Posted in the Advanced Algebra Forum
    Replies: 8
    Last Post: January 11th 2009, 01:35 PM
  5. Subspace of R3
    Posted in the Advanced Algebra Forum
    Replies: 3
    Last Post: December 14th 2008, 08:36 AM

Search Tags


/mathhelpforum @mathhelpforum