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Math Help - proof

  1. #1
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    proof

    Let A={a_1,a_2,a_3,...} be a countably infinite set, and let A'=A-{a_1}. Prove that |A|=|A'|.
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  2. #2
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    Quote Originally Posted by natewalker205 View Post
    Let A={a_1,a_2,a_3,...} be a countably infinite set, and let A'=A-{a_1}. Prove that |A|=|A'|.
    Hint: f:A \to A',f(a_i) = a_{i+1} is a bijection.
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  3. #3
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    onto

    i can't get the onto part of the bijection
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  4. #4
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    Quote Originally Posted by natewalker205 View Post
    i can't get the onto part of the bijection
    Let a_k \in A', a_{k-1} \in A.
    This is meaningful because k > 1.
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