None
Conclusion:
hyp,M,N:Formula List. q,r:Formula. a:Assignment. a |= <hyp, q::r::(M @ N)> a |= <hyp, M @ (qr::N)>
1. a |= <hyp, M @ (qr::N)>2. a |= <hyp, q::r::(M @ N)>
2. a |= <hyp, q::r::(M @ N)>