2 player zero-sum-game rock paper scissors expected loss











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For the Rock-Paper-Scissors game, I am trying to determine the expected loss for P1.



The following matrix displays how much P1 has lost:

A:

| 0 1 -1 |

| -1 0 1 |

| 1 -1 0 |



I am trying to find the expected loss for P1 when P1 uses mixed strategy x = (x1, x2, x3) and P2 uses mixed strategy y (y1, y2, y3)



I am not sure how to do this?



EDIT:
My attempt is thinking that if I should always have a 1/3 chance of winning, right?










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  • There are only $9$ things that can happen. Figure out their probabilities and add up the expected gains and losses.
    – saulspatz
    Nov 15 at 3:10










  • the solution proposed by saulspatz can be written elegantly in terms of $A$, $x$ and $y$
    – LinAlg
    Nov 15 at 16:29










  • I will attempt this, and post an answer. Thank you for the feed back.
    – Jerry M.
    Nov 15 at 17:03










  • It's true that you can always break even by playing $x = (1/3,1/3,1/3)$. But you can possibly do better, depending on P2's strategy. If P2 always plays rock, then you can always play paper and win every time.
    – Théophile
    Nov 17 at 21:12












  • @Théophile thank you for the feedback. I know this is dumb question but I am trying so hard to understand it
    – Jerry M.
    Nov 17 at 21:14















up vote
0
down vote

favorite












For the Rock-Paper-Scissors game, I am trying to determine the expected loss for P1.



The following matrix displays how much P1 has lost:

A:

| 0 1 -1 |

| -1 0 1 |

| 1 -1 0 |



I am trying to find the expected loss for P1 when P1 uses mixed strategy x = (x1, x2, x3) and P2 uses mixed strategy y (y1, y2, y3)



I am not sure how to do this?



EDIT:
My attempt is thinking that if I should always have a 1/3 chance of winning, right?










share|cite|improve this question
























  • There are only $9$ things that can happen. Figure out their probabilities and add up the expected gains and losses.
    – saulspatz
    Nov 15 at 3:10










  • the solution proposed by saulspatz can be written elegantly in terms of $A$, $x$ and $y$
    – LinAlg
    Nov 15 at 16:29










  • I will attempt this, and post an answer. Thank you for the feed back.
    – Jerry M.
    Nov 15 at 17:03










  • It's true that you can always break even by playing $x = (1/3,1/3,1/3)$. But you can possibly do better, depending on P2's strategy. If P2 always plays rock, then you can always play paper and win every time.
    – Théophile
    Nov 17 at 21:12












  • @Théophile thank you for the feedback. I know this is dumb question but I am trying so hard to understand it
    – Jerry M.
    Nov 17 at 21:14













up vote
0
down vote

favorite









up vote
0
down vote

favorite











For the Rock-Paper-Scissors game, I am trying to determine the expected loss for P1.



The following matrix displays how much P1 has lost:

A:

| 0 1 -1 |

| -1 0 1 |

| 1 -1 0 |



I am trying to find the expected loss for P1 when P1 uses mixed strategy x = (x1, x2, x3) and P2 uses mixed strategy y (y1, y2, y3)



I am not sure how to do this?



EDIT:
My attempt is thinking that if I should always have a 1/3 chance of winning, right?










share|cite|improve this question















For the Rock-Paper-Scissors game, I am trying to determine the expected loss for P1.



The following matrix displays how much P1 has lost:

A:

| 0 1 -1 |

| -1 0 1 |

| 1 -1 0 |



I am trying to find the expected loss for P1 when P1 uses mixed strategy x = (x1, x2, x3) and P2 uses mixed strategy y (y1, y2, y3)



I am not sure how to do this?



EDIT:
My attempt is thinking that if I should always have a 1/3 chance of winning, right?







linear-programming game-theory nash-equilibrium






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edited Nov 17 at 21:08

























asked Nov 15 at 2:58









Jerry M.

1011




1011












  • There are only $9$ things that can happen. Figure out their probabilities and add up the expected gains and losses.
    – saulspatz
    Nov 15 at 3:10










  • the solution proposed by saulspatz can be written elegantly in terms of $A$, $x$ and $y$
    – LinAlg
    Nov 15 at 16:29










  • I will attempt this, and post an answer. Thank you for the feed back.
    – Jerry M.
    Nov 15 at 17:03










  • It's true that you can always break even by playing $x = (1/3,1/3,1/3)$. But you can possibly do better, depending on P2's strategy. If P2 always plays rock, then you can always play paper and win every time.
    – Théophile
    Nov 17 at 21:12












  • @Théophile thank you for the feedback. I know this is dumb question but I am trying so hard to understand it
    – Jerry M.
    Nov 17 at 21:14


















  • There are only $9$ things that can happen. Figure out their probabilities and add up the expected gains and losses.
    – saulspatz
    Nov 15 at 3:10










  • the solution proposed by saulspatz can be written elegantly in terms of $A$, $x$ and $y$
    – LinAlg
    Nov 15 at 16:29










  • I will attempt this, and post an answer. Thank you for the feed back.
    – Jerry M.
    Nov 15 at 17:03










  • It's true that you can always break even by playing $x = (1/3,1/3,1/3)$. But you can possibly do better, depending on P2's strategy. If P2 always plays rock, then you can always play paper and win every time.
    – Théophile
    Nov 17 at 21:12












  • @Théophile thank you for the feedback. I know this is dumb question but I am trying so hard to understand it
    – Jerry M.
    Nov 17 at 21:14
















There are only $9$ things that can happen. Figure out their probabilities and add up the expected gains and losses.
– saulspatz
Nov 15 at 3:10




There are only $9$ things that can happen. Figure out their probabilities and add up the expected gains and losses.
– saulspatz
Nov 15 at 3:10












the solution proposed by saulspatz can be written elegantly in terms of $A$, $x$ and $y$
– LinAlg
Nov 15 at 16:29




the solution proposed by saulspatz can be written elegantly in terms of $A$, $x$ and $y$
– LinAlg
Nov 15 at 16:29












I will attempt this, and post an answer. Thank you for the feed back.
– Jerry M.
Nov 15 at 17:03




I will attempt this, and post an answer. Thank you for the feed back.
– Jerry M.
Nov 15 at 17:03












It's true that you can always break even by playing $x = (1/3,1/3,1/3)$. But you can possibly do better, depending on P2's strategy. If P2 always plays rock, then you can always play paper and win every time.
– Théophile
Nov 17 at 21:12






It's true that you can always break even by playing $x = (1/3,1/3,1/3)$. But you can possibly do better, depending on P2's strategy. If P2 always plays rock, then you can always play paper and win every time.
– Théophile
Nov 17 at 21:12














@Théophile thank you for the feedback. I know this is dumb question but I am trying so hard to understand it
– Jerry M.
Nov 17 at 21:14




@Théophile thank you for the feedback. I know this is dumb question but I am trying so hard to understand it
– Jerry M.
Nov 17 at 21:14










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The expected payoff for $P1$ when he plays the mixed strategy $x$ and his opponent plays the mixed strategy $y$ is $x A y^top$.






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    1 Answer
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    1 Answer
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    up vote
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    The expected payoff for $P1$ when he plays the mixed strategy $x$ and his opponent plays the mixed strategy $y$ is $x A y^top$.






    share|cite|improve this answer

























      up vote
      0
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      The expected payoff for $P1$ when he plays the mixed strategy $x$ and his opponent plays the mixed strategy $y$ is $x A y^top$.






      share|cite|improve this answer























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        up vote
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        down vote









        The expected payoff for $P1$ when he plays the mixed strategy $x$ and his opponent plays the mixed strategy $y$ is $x A y^top$.






        share|cite|improve this answer












        The expected payoff for $P1$ when he plays the mixed strategy $x$ and his opponent plays the mixed strategy $y$ is $x A y^top$.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Nov 17 at 18:10









        mlc

        4,83431332




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