This is unsolved for a long time in MathOverflow. It's a card-game-problem, so I think it's more appropriate for cstheory, but I'm not sure, so I post a meta problem here to ensure.
I think that reposting is fine, but if you repost, please do the following:
- Link in both directions.
- Try to take care of the questions on both sites. That is, if you receive an answer on one site, let the users of the other site know. I understand this is not always possible, though.
You may want to include Guillaume Brunerie’s reformulation in natural language in the comment to the question on MathOverflow; it helped me understand the rules.