3.I.5H3 . \mathrm{I} . 5 \mathrm{H} \quad

Optimization
Part IB, 2003

Two players A and B play a zero-sum game with the pay-off matrix

\begin{tabular}{r|rrr} & B1B_{1} & B2B_{2} & B3B_{3} \ \hlineA1A_{1} & 4 & 2-2 & 5-5 \ A2A_{2} & 2-2 & 4 & 3 \ A3A_{3} & 3-3 & 6 & 2 \ A4A_{4} & 3 & 8-8 & 6-6 \end{tabular}

Here, the (i,j)(i, j) entry of the matrix indicates the pay-off to player A if he chooses move AiA_{i} and player B\mathrm{B} chooses move BjB_{j}. Show that the game can be reduced to a zero-sum game with 2×22 \times 2 pay-off matrix.

Determine the value of the game and the optimal strategy for player A.