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Prove that ordinal arithmetic is associative

  1. Feb 8, 2016 #1
    1. The problem statement, all variables and given/known data
    Let a, b, c be ordinals.
    Prove that a+(b+c)=(a+b)+c

    2. Relevant equations

    3. The attempt at a solution

    I looked at a set theory book by Jech and he says Prove by induction on c.
    Should I look at the case where its true for c+1
  2. jcsd
  3. Feb 8, 2016 #2
    Come on. There's no single thing you could attempt here??
    What is transfinite induction? What do you need to do for it?
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