Enhancing pseudo-telepathy in the Magic Square game
  We study the possibility of reversing an action of a quantum channel. Our principal objective is to find a specific channel that reverses as accurately as possible an action of a given quantum channel. To achieve this goal we use semidefinite programming. We show the benefits of our method using the quantum pseudo-telepathy Magic Square game with noise. Our strategy is to move the pseudo-telepathy region to higher noise values. We show that it is possible to reverse the action of a noise channel using semidefinite programming. 
{\L}ukasz Pawela, Piotr Gawron, Zbigniew Pucha{\l}a, Jan S{\l}adkowski
quant-ph