gringo: generally that doesn't happen, since most everyone here will learn quickly what stones are dead; but if you ran into that situation, the best plan would be to just go on killing those groups you think are dead. Yes, you'll be playing in your own territory, but he'll have to make a move too which will either give you a point (moving in your territory) or take one away from him (moving in his own territory. It would be foolish to carry on this way, but eventually his dead groups will be really dead and the game will be so slanted he'll have no choice but to resign.

If even then he refuses to submit, you can play until there's no dead groups and a bunch of one-square openings left on the board. At that point, nobody can move, there are no contested groups, and the game will be over.

I suppose there could be a case where someone refuses to accept defeat EVER, but I hope they'll be very rare. Perhaps that's a good question...in the off change that someone never accepts the result, how shall the game end? I know of no rules to govern that situation, since generally it would be so distasteful that it does not happen.