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Among the following sets, identify all pairs of equal sets?

  1. Feb 13, 2013 #1
    1. Among the following sets, identify all pairs of equal sets? What is the cardinality of each one
    of the sets?

    a) ∅
    b) {∅}
    c) {{∅}}
    d) {∅,{∅}}
    e) {∅} [itex]\bigcap[/itex] {{∅}}
    f) {{∅},∅}



    I would truly appreciate if you explain a bit.
    Thank you in advance.
    _____________________________________________
    my answer:

    a) Zero
    b) one
    c) one
    d) two
    e) not sure but i think it's two or zero.???
    f) two
     
  2. jcsd
  3. Feb 13, 2013 #2

    haruspex

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    Re: Cardinality

    All correct. For e), what do you think the set is?
     
  4. Feb 13, 2013 #3
    Re: Cardinality

    I believe zero.
    btw thank you.
     
  5. Feb 13, 2013 #4

    haruspex

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    Re: Cardinality

    Yes, it's null.
     
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