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Every prime greater than 7 can be written as the sum of two primes

  1. Jul 12, 2012 #1

    DbL

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    "Every prime greater than 7, P, can be written as the sum of two primes, A and B, and the subtraction of a third prime, C, in the form (A+B)-C, where A is not identical to B or C, B is not identical to C, and A, B, and C are less than P."

    True?
     
  2. jcsd
  3. Jul 12, 2012 #2
    Can this be done with 11?
     
    Last edited: Jul 12, 2012
  4. Jul 12, 2012 #3
    Do you mean prime or relatively prime?
     
  5. Jul 12, 2012 #4

    DbL

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    (7+5)-1
     
  6. Jul 12, 2012 #5

    DbL

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    prime
     
  7. Jul 12, 2012 #6

    Curious3141

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    Homework Helper

    1 is not a prime.
     
  8. Jul 12, 2012 #7

    DbL

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    That is correct.

    The number 1 is not considered a prime, although it is a unique integer. The definition of a "prime" number is one that has exactly TWO factors: itself and 1. So the number 1, having only ONE factor, itself, does not meet the definition.
     
  9. Jul 12, 2012 #8

    Curious3141

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    OK, C (defined to be prime) cannot be 1.

    Your proposition is disproven.

    11 is a counterexample.
     
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