q=(1,12) p=(1,12) = (1-b1*B(1) -b2*B(12))/(1-a1*B(1)-a2*B(12) ) * err
q=(1)(12) p=(1) (12) = [(1-b1*B(1))*(1 -b2*B(12))]/[(1-a1*B(1))*(1-a2*B(12) )] * err
where b's and a's are parameters and B is a backshift(lag) operater. B(1) = shift 1 B(12) = shift 12
sometimes (1)(12) notation refers to as factored(pr ...