If ∀A ∈ PX , ∀B ∈ PY , |A| < |B| Then ∃A ∈ PX , ∃B ∈ PY , A ⊂ B












-1












$begingroup$


X and Y are non-empty sets , X c Y (subset ) and Px is a partition of X and Py is a partition of Y .



How can I prove that this statement is true or false :



If ∀A ∈ PX, ∀B ∈ PY ,|A| < |B|



Then ∃A ∈ PX, ∃B ∈ PY , A ⊂ B



Thank you .



Ps: what I understood is that since XcY then A that belongs to X belongs to Y as well and since the cardinality of A is smaller than B then A is likely to be a subset of B . My guess is this statement is true but I have no idea how to prove it , which method to use ? I don’t know how to start my proof .










share|cite|improve this question











$endgroup$

















    -1












    $begingroup$


    X and Y are non-empty sets , X c Y (subset ) and Px is a partition of X and Py is a partition of Y .



    How can I prove that this statement is true or false :



    If ∀A ∈ PX, ∀B ∈ PY ,|A| < |B|



    Then ∃A ∈ PX, ∃B ∈ PY , A ⊂ B



    Thank you .



    Ps: what I understood is that since XcY then A that belongs to X belongs to Y as well and since the cardinality of A is smaller than B then A is likely to be a subset of B . My guess is this statement is true but I have no idea how to prove it , which method to use ? I don’t know how to start my proof .










    share|cite|improve this question











    $endgroup$















      -1












      -1








      -1





      $begingroup$


      X and Y are non-empty sets , X c Y (subset ) and Px is a partition of X and Py is a partition of Y .



      How can I prove that this statement is true or false :



      If ∀A ∈ PX, ∀B ∈ PY ,|A| < |B|



      Then ∃A ∈ PX, ∃B ∈ PY , A ⊂ B



      Thank you .



      Ps: what I understood is that since XcY then A that belongs to X belongs to Y as well and since the cardinality of A is smaller than B then A is likely to be a subset of B . My guess is this statement is true but I have no idea how to prove it , which method to use ? I don’t know how to start my proof .










      share|cite|improve this question











      $endgroup$




      X and Y are non-empty sets , X c Y (subset ) and Px is a partition of X and Py is a partition of Y .



      How can I prove that this statement is true or false :



      If ∀A ∈ PX, ∀B ∈ PY ,|A| < |B|



      Then ∃A ∈ PX, ∃B ∈ PY , A ⊂ B



      Thank you .



      Ps: what I understood is that since XcY then A that belongs to X belongs to Y as well and since the cardinality of A is smaller than B then A is likely to be a subset of B . My guess is this statement is true but I have no idea how to prove it , which method to use ? I don’t know how to start my proof .







      discrete-mathematics






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      share|cite|improve this question













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      share|cite|improve this question








      edited Feb 1 at 21:40







      soso xoxo

















      asked Feb 1 at 18:26









      soso xoxososo xoxo

      85




      85






















          1 Answer
          1






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          0












          $begingroup$

          X = { 1,2,3,4,5,6 }.

          Y = { 1,2,3,4,5,6,7 }.

          PX = { {1,4}, {2,5}, {3,6} }.

          PY = { {1,2,3}, {4,5,6,7} }.

          What does that example show?






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            Thank you that helped me see that A is not necessary a subset of B
            $endgroup$
            – soso xoxo
            Feb 2 at 2:52












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          1 Answer
          1






          active

          oldest

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          active

          oldest

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          active

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          0












          $begingroup$

          X = { 1,2,3,4,5,6 }.

          Y = { 1,2,3,4,5,6,7 }.

          PX = { {1,4}, {2,5}, {3,6} }.

          PY = { {1,2,3}, {4,5,6,7} }.

          What does that example show?






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            Thank you that helped me see that A is not necessary a subset of B
            $endgroup$
            – soso xoxo
            Feb 2 at 2:52
















          0












          $begingroup$

          X = { 1,2,3,4,5,6 }.

          Y = { 1,2,3,4,5,6,7 }.

          PX = { {1,4}, {2,5}, {3,6} }.

          PY = { {1,2,3}, {4,5,6,7} }.

          What does that example show?






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            Thank you that helped me see that A is not necessary a subset of B
            $endgroup$
            – soso xoxo
            Feb 2 at 2:52














          0












          0








          0





          $begingroup$

          X = { 1,2,3,4,5,6 }.

          Y = { 1,2,3,4,5,6,7 }.

          PX = { {1,4}, {2,5}, {3,6} }.

          PY = { {1,2,3}, {4,5,6,7} }.

          What does that example show?






          share|cite|improve this answer











          $endgroup$



          X = { 1,2,3,4,5,6 }.

          Y = { 1,2,3,4,5,6,7 }.

          PX = { {1,4}, {2,5}, {3,6} }.

          PY = { {1,2,3}, {4,5,6,7} }.

          What does that example show?







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited Feb 2 at 1:27

























          answered Feb 2 at 1:15









          William ElliotWilliam Elliot

          9,1562820




          9,1562820












          • $begingroup$
            Thank you that helped me see that A is not necessary a subset of B
            $endgroup$
            – soso xoxo
            Feb 2 at 2:52


















          • $begingroup$
            Thank you that helped me see that A is not necessary a subset of B
            $endgroup$
            – soso xoxo
            Feb 2 at 2:52
















          $begingroup$
          Thank you that helped me see that A is not necessary a subset of B
          $endgroup$
          – soso xoxo
          Feb 2 at 2:52




          $begingroup$
          Thank you that helped me see that A is not necessary a subset of B
          $endgroup$
          – soso xoxo
          Feb 2 at 2:52


















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