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I Problem when solving example with differential forms

  1. Apr 9, 2017 #1
    Hi was reading about differential forms, when I tried to solve the example EPOnpJe.png given in this pdf https://www.rose-hulman.edu/~bryan/lottamath/difform.pdf. According to it, the answer is that on the image above. But when I tried to solve this same example by following the expression for ##w## given in this pdf http://www.bose.res.in/~amitabha/diffgeom/chap13.pdf, namely that a p-form ##w## can be written as $$\frac{1}{p!}w_{\mu_1 ... \mu_p}dx^{\mu_1} \wedge \ ... \ \wedge dx^{\mu_p}$$ and that ##w##, in this case, applied to two vectors ##v_{(1)}## and ##v_{(2)}## is ##w_{i j}v_{(1)}^i v_{(2)}^j##, the answer that I'm getting diverges from that given in the other pdf. What is wrong?
     
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  3. Apr 9, 2017 #2
    I noticed that the only problem is that in one pdf they introduce a factor ##1 / p!## while in the other they don't. My answer is off by a factor of ##1/2## in this case. So what is the correct?

    I guess if one were going to consider only the anti-symmetric part of ##A(u)B(v)## then a factor of ##1/2## would be needed. But if one were considering ##A(u)B(v) - A(v)B(u)## it is not clear whether a factor of ##1/2## is needed. (##A, B## are one-forms and ##v, u## are vectors)
     
  4. Apr 14, 2017 #3

    haushofer

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    You ask us what's wrong with your calculation we do not get to see?
     
  5. Apr 14, 2017 #4
    After this thread, I noticed that I have forgotten to summing over all components and that was the cause of not getting the right result.
    Thanks
     
  6. Apr 15, 2017 #5

    haushofer

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    Look, if you want people to invest time to help you, you shouldn't expect them to have paranormal abilities.

    I've read a couple of your questions now and they seem highly confused, giving me the impression that you're studying stuff without the right background.
     
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