Enjoy ...
a1 = [1 2];
a2 = [1 2 3];
res = a1.' - a2 ; res = res(:).'
Pay attention to the fact that a1 and a2 must be row-vectors (= not column-vectors), otherwise you will have to modify a little bit.
The general idea is that a1.' is a column vector, and a2 is a row-vector. In Matlab colum-vector (op) row-vector returns a matrix, the entries of which are the result of the operation between each couple of elements of the two vectors.
