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Implication of a set of zeros with positive measure

  1. Apr 16, 2013 #1
    I have a non-zero measured subset [itex]X\subseteq\mathbb{R}^{n}[/itex] on which [itex]\sum_{i=1}^{n}\psi_{i}x_{i}=0[/itex] for all [itex]x=(x_{1},\ldots,x_{n})[/itex] in [itex]X[/itex]. How can I show that [itex]\psi_{i}=0[/itex] for [itex]i=1,\ldots,n[/itex]?
  2. jcsd
  3. Apr 16, 2013 #2


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    A non-zero ψ_i for at least one i would allow to solve the sum equation for ...
    This will eventually lead to a contradiction with "non-zero measure".
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