Results 1 to 2 of 2

Math Help - functions

  1. #1
    Super Member
    Joined
    Aug 2009
    Posts
    639

    functions

    when a question states that A is isomorphic to B, do we define the function from A to B or from B to A?

    im quite confused about how we should define the function..

    thanks
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor Bruno J.'s Avatar
    Joined
    Jun 2009
    From
    Canada
    Posts
    1,266
    Thanks
    1
    Awards
    1
    By "the function", I suppose you mean "the isomorphism"?

    Usually, when we say A \cong B, we mean that there exists an isomorphism f: A \rightarrow B. (There could be more than one.) But it doesn't really matter which direction we suppose the arrow to be going, because f^{-1} is an isomorphism B \rightarrow A. (Prove it!)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 0
    Last Post: April 15th 2010, 05:50 PM
  2. Replies: 3
    Last Post: February 23rd 2010, 04:54 PM
  3. Replies: 11
    Last Post: November 15th 2009, 11:22 AM
  4. Replies: 7
    Last Post: August 12th 2009, 04:41 PM
  5. Replies: 1
    Last Post: April 15th 2008, 09:00 AM

Search Tags


/mathhelpforum @mathhelpforum