[Jan Olligs]

Of course I know what antimatter is and what it does. That's why I think that it would be an offensive part of the robot and therefore forbidden. Or they could try to power the 'bot with matter-amtimatter annihalations which would blast the whole US away (if they use macroscopic amounts).
That's why I thought that antimatter had another meaning than the normal physical one, but obviously it doesn't.
And although there is no such thing antigravity, it would be really nice to have a device that causes it on the robot: No more weight limitations and a great robot speed...