Does this game have a core?












1












$begingroup$


I'm trying to find the core of this cooperative game:



$N = {1,2,3}$ and $v({1})=24$, $v({2})=24$, $v({3})=26$, $v({1,2})=42$, $v({1,3})=44$, $v({N})=52$.



My solution:



$x_1 ge 24$
$x_2 ge 24$
$x_3 ge 26$



$x_1+x_2 ge 42$
$x_1+x_3 ge 34$
$x_2+x_3 ge 44$
$x_1+x_2+x_3=52$



Manipulating the last four expressions I obtained the following inequalities:



$x_1 le 10$
$x_2 le 18$
$x_3 le 8$



Which (I think) are in contrast with the first three, so the core should be empty (?).



My book instead gives as a solution: $co {(24, 18, 10), (18, 24, 10), (8, 24, 20), (8, 18, 26) } $.
Solution diagram



What am I missing?










share|cite|improve this question









$endgroup$

















    1












    $begingroup$


    I'm trying to find the core of this cooperative game:



    $N = {1,2,3}$ and $v({1})=24$, $v({2})=24$, $v({3})=26$, $v({1,2})=42$, $v({1,3})=44$, $v({N})=52$.



    My solution:



    $x_1 ge 24$
    $x_2 ge 24$
    $x_3 ge 26$



    $x_1+x_2 ge 42$
    $x_1+x_3 ge 34$
    $x_2+x_3 ge 44$
    $x_1+x_2+x_3=52$



    Manipulating the last four expressions I obtained the following inequalities:



    $x_1 le 10$
    $x_2 le 18$
    $x_3 le 8$



    Which (I think) are in contrast with the first three, so the core should be empty (?).



    My book instead gives as a solution: $co {(24, 18, 10), (18, 24, 10), (8, 24, 20), (8, 18, 26) } $.
    Solution diagram



    What am I missing?










    share|cite|improve this question









    $endgroup$















      1












      1








      1





      $begingroup$


      I'm trying to find the core of this cooperative game:



      $N = {1,2,3}$ and $v({1})=24$, $v({2})=24$, $v({3})=26$, $v({1,2})=42$, $v({1,3})=44$, $v({N})=52$.



      My solution:



      $x_1 ge 24$
      $x_2 ge 24$
      $x_3 ge 26$



      $x_1+x_2 ge 42$
      $x_1+x_3 ge 34$
      $x_2+x_3 ge 44$
      $x_1+x_2+x_3=52$



      Manipulating the last four expressions I obtained the following inequalities:



      $x_1 le 10$
      $x_2 le 18$
      $x_3 le 8$



      Which (I think) are in contrast with the first three, so the core should be empty (?).



      My book instead gives as a solution: $co {(24, 18, 10), (18, 24, 10), (8, 24, 20), (8, 18, 26) } $.
      Solution diagram



      What am I missing?










      share|cite|improve this question









      $endgroup$




      I'm trying to find the core of this cooperative game:



      $N = {1,2,3}$ and $v({1})=24$, $v({2})=24$, $v({3})=26$, $v({1,2})=42$, $v({1,3})=44$, $v({N})=52$.



      My solution:



      $x_1 ge 24$
      $x_2 ge 24$
      $x_3 ge 26$



      $x_1+x_2 ge 42$
      $x_1+x_3 ge 34$
      $x_2+x_3 ge 44$
      $x_1+x_2+x_3=52$



      Manipulating the last four expressions I obtained the following inequalities:



      $x_1 le 10$
      $x_2 le 18$
      $x_3 le 8$



      Which (I think) are in contrast with the first three, so the core should be empty (?).



      My book instead gives as a solution: $co {(24, 18, 10), (18, 24, 10), (8, 24, 20), (8, 18, 26) } $.
      Solution diagram



      What am I missing?







      game-theory






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      share|cite|improve this question











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      share|cite|improve this question










      asked Feb 1 at 1:39









      ccmptccmpt

      82




      82






















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          $begingroup$

          You are completely right, the core must be empty. The quickest way to see that is to use the inequalites of the singleton coalitions, adding them up gives $sum_{i in N} x_{i} ge 24 + 24 +26 = 74 > 52 = v(N)$. Hence, the Pareto-efficiency constraint is violated, the core must be empty.



          I guess that this is a misprint in the book. By the way, due to the above constraints set the value of coalition ${1,3}$ should be $34$ and that of coalition ${2,3}$ must be $44$.






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            Thank you for your help!
            $endgroup$
            – ccmpt
            Feb 1 at 9:57














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          $begingroup$

          You are completely right, the core must be empty. The quickest way to see that is to use the inequalites of the singleton coalitions, adding them up gives $sum_{i in N} x_{i} ge 24 + 24 +26 = 74 > 52 = v(N)$. Hence, the Pareto-efficiency constraint is violated, the core must be empty.



          I guess that this is a misprint in the book. By the way, due to the above constraints set the value of coalition ${1,3}$ should be $34$ and that of coalition ${2,3}$ must be $44$.






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            Thank you for your help!
            $endgroup$
            – ccmpt
            Feb 1 at 9:57


















          1












          $begingroup$

          You are completely right, the core must be empty. The quickest way to see that is to use the inequalites of the singleton coalitions, adding them up gives $sum_{i in N} x_{i} ge 24 + 24 +26 = 74 > 52 = v(N)$. Hence, the Pareto-efficiency constraint is violated, the core must be empty.



          I guess that this is a misprint in the book. By the way, due to the above constraints set the value of coalition ${1,3}$ should be $34$ and that of coalition ${2,3}$ must be $44$.






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            Thank you for your help!
            $endgroup$
            – ccmpt
            Feb 1 at 9:57
















          1












          1








          1





          $begingroup$

          You are completely right, the core must be empty. The quickest way to see that is to use the inequalites of the singleton coalitions, adding them up gives $sum_{i in N} x_{i} ge 24 + 24 +26 = 74 > 52 = v(N)$. Hence, the Pareto-efficiency constraint is violated, the core must be empty.



          I guess that this is a misprint in the book. By the way, due to the above constraints set the value of coalition ${1,3}$ should be $34$ and that of coalition ${2,3}$ must be $44$.






          share|cite|improve this answer











          $endgroup$



          You are completely right, the core must be empty. The quickest way to see that is to use the inequalites of the singleton coalitions, adding them up gives $sum_{i in N} x_{i} ge 24 + 24 +26 = 74 > 52 = v(N)$. Hence, the Pareto-efficiency constraint is violated, the core must be empty.



          I guess that this is a misprint in the book. By the way, due to the above constraints set the value of coalition ${1,3}$ should be $34$ and that of coalition ${2,3}$ must be $44$.







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited Feb 1 at 10:16

























          answered Feb 1 at 9:43









          Holger I. MeinhardtHolger I. Meinhardt

          798147




          798147












          • $begingroup$
            Thank you for your help!
            $endgroup$
            – ccmpt
            Feb 1 at 9:57




















          • $begingroup$
            Thank you for your help!
            $endgroup$
            – ccmpt
            Feb 1 at 9:57


















          $begingroup$
          Thank you for your help!
          $endgroup$
          – ccmpt
          Feb 1 at 9:57






          $begingroup$
          Thank you for your help!
          $endgroup$
          – ccmpt
          Feb 1 at 9:57




















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