I would like to know if there is a possibility with Mathematica to define let's say v1, v2, v3, v4 as general vectors and l1,l2,l3,l4 as scalars such that when I enter
(l1*v1 + l2*v2).(l3*v3 + l4*v4), it returns
l1*l3*(v1.v2) + l1*l4*(v1.v4) + l2*l3*(v2.v3) + l2*l4*(v2.v4)
Thank you in advance for your help.