a_1 = \left( {{\rm 1}{\rm ,0}{\rm ,1}{\rm , - 2}} \right),a_2 = \left( {0,1,0,1} \right),b_1 = \left( {1, - 1, - 2,0} \right),b_2 = \left( {0,2,3, - 1} \right)