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Homework Help: Interesting logic question

  1. Nov 6, 2007 #1
    1. How do you prove, using SD, that ((A>B)>A)>A?


    3. I tried to first assume (A>B)>A. Then I made a sub-derivation, assuming ~A. In this sub-derivation, I need to derive a contradiction. How?
     
  2. jcsd
  3. Nov 7, 2007 #2

    cristo

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    Staff Emeritus
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    What does your symbol ">" mean?
     
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