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Symbol phi

  1. Feb 21, 2010 #1
    So for my homework I have to prove (or disprove) this statement:

    If U, V are two subspaces of Rn then U [tex]\cap[/tex] V [tex]\neq[/tex] [tex]\phi[/tex].

    I just want to make sure; [tex]\phi[/tex] is the null set right? The set with nothing in it?
  2. jcsd
  3. Feb 21, 2010 #2
    Yes it's the empty set. However the symbol isn't the greek letter phi, but a symbol of its own based on the letter Ø (a letter in some alphabets).

    [tex]\phi \quad \emptyset[/tex]
    The first is phi and the second is "empty set".

    See http://en.wikipedia.org/wiki/Empty_set#Notation" for a bit more information.
    Last edited by a moderator: Apr 24, 2017
  4. Feb 21, 2010 #3
    This is why I got used to writing [tex]\varphi[/tex] for phi. Although I never learned if there is a proper time to use [tex]\phi[/tex] and a proper time to use [tex]\varphi[/tex].
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