[JewishDan18]

I'm toying around with calculating OPR, but I'm running into something of a road block. The matrix of team pairs is supposed to be diagonally dominant, and thus invertible, but I don't see how this is. If Team A played with two other teams in only one match, the diagonal element would be 1 and there would be two other 1's in Team A's row. This row alone would violate the conditions for diagonal dominance. I know I'm missing something simple, does anyone have any pointers?