Kronecker Delta and vector form of q_(i,j) q_(m,mj)

Romik

guys,

we know ∇q=q_i,j and ∇ ∇.q=q_i,ij

but what will happen if we have q_i,jq_m,mj ? (sum on j)

I know some terms of ∇q∇ ∇.q will drop due to that summation. so the question is what is the right expression in vector form for that term.

thanks