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THE PRISONER'S DIELEMMA


    Say, there are two persons Tom and Bob in a town.  Both attempted to rob a bank and caught.  During interrogation, the police give each an option.

   That is , " if  you confess and your friend keeps silent,   you will go free and your friend will be behind the bars for a year.  If both of you prefer to keep mum, both may get one month  jail term.  If both of you confess, both will be sentenced for 6 months.  It is up to you to decide."

  Hence both prisoners are put in a dilemma.  But it can be solved easily using math.  Let us get the help of matrix.

      Let us reduce the situations to numbers - happiness score.
                                                                                 happiness score
Jail term-   0 month                                                        4
Jail term -  1 month                                                        3
Jail term -  6 months                                                       2
Jail term -  12 months                                                     1

      Everybody wishes to increase the happiness score.

 Now the matrix
S FOR SILENT, C FOR CONFESSION
================================================
  BOB      Tom                               Bob      Tom
 S             S                                     S           C
 3             3                                      1          4

 Bob       Tom                                  Bob       Tom
 C            S                                      C           C
 4             1                                       2          2
================================================
     Both Bob and Tom want to reduce jail term and both do not rely on each other.  Hence both take the option of "confess-confess" where the jail term is somewhat minimum and the happiness score is somewhat big.  If both rely strongly in each other, they can opt for 'silent-silent' situation.  But it is very rare.

      Finally justice system has own. Both give evidence and also serve sentence.  We all face prisoner's dilemma everyday and take decisions.
       Suppose, there is a political tension between two neighboring countries. They are at the edge of war.  Who will attack first? Who will defend?   This also similar to prisoner's dilemma and we can solve in the same way.  Since first attack gives huge advantage in a war, both will attack and ultimately engage in the war.
     The prisoner's dilemma arises in games often.
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