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What is the axis label for the fourth dimension?

  1. Dec 25, 2012 #1

    Jow

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    I have a quick question. On a typical cartesian coordinate system you have the x-axis and y-axis for two dimensions and the z-axis for the third. What would you label the axis representing the fourth dimension?

    I know this is a bit of a silly and unimportant question, but I was thinking about function notation (ie: f(x), f(x,y) , f(x,y,z)) and I was wondering what would come next; f(x,y,z,?)
     
  2. jcsd
  3. Dec 25, 2012 #2
    w is the usual convention, but you CAN call it whatever you want.
     
  4. Dec 26, 2012 #3
    Fourth dimension is frequently time--denoted with letter t.
     
  5. Dec 26, 2012 #4
    Physics frequently deals with time-like dimensions, but this isn't particularly common or useful in mathematics, and "time" as a dimension behaves differently than what the OP is asking about. When dealing with, say, Euclidean 4-space, Mandelbroth is right that w is the usual convention, but it's fairly common to just use, say, an indexed family of x's (i.e. x1 ... x4).
     
  6. Dec 27, 2012 #5

    Jow

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    Thanks for the answer. It was bugging me because google was not being helpful.
     
  7. Dec 29, 2012 #6

    HallsofIvy

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    Staff Emeritus
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    Google is seldom helpful if you cannot pose a specific question- GIGO.
     
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