There are co-champions. We are just talking seeding for the Big Ten Tournament. What do you mean circular logic? Say you have teams 2-5 all tied. The first tie breaker would be combined record of all games between those four teams. This weeds out teams 2 and 5, 3 and 4 are still tied. The next tie breaker would be teams 3 and 4 records vs the #1 seed, then the new #2 seed, and then the #5 seed, then 6, 7, 8, 9, 10, 11. I don't know the next level of tie breaker. I have a hard time believing it could ever get that far.