MTG doesn't require solving the halting problem because, if neither player nor the referee can come up with a way to halt a loop, then the match ends (long ago,

MTG doesn't require solving the halting problem because, if neither player nor the referee can come up with a way to halt a loop, then the match ends (long ago, when I played, it ended in a draw; other comments in this thread suggest that a player intentionally doing this may incur a loss now).