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Homework Help: Numerical equivalence of sets

  1. Feb 16, 2010 #1
    1. Define numerical equivalence of sets

    2. I'm not sure how in depth the definition needs to be, how is my current def?

    3. X is numerically equivalent to Y if [tex]\exists[/tex]F:X[tex]\rightarrow[/tex]Y that is bijective or there are two injective functions f:X[tex]\rightarrow[/tex]Y and g:Y[tex]\rightarrow[/tex]X
  2. jcsd
  3. Feb 16, 2010 #2


    Staff: Mentor

    Seems reasonable. I haven't seen the term "numerical equivalence" used. What I have seen is "same cardinality." I don't think you need to have two injective functions; just one bijective function should do the job.
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