3.1 Minkowski addition and subtraction
The aim of this chapter is a more systematic study of Minkowski addition. In the present section we first collect some elementary formal properties of this addition and then investigate its convexifying effect. After that, we introduce a certain coun -terpart to Minkowski addition, a useful operation that has been called Minkowski subtraction.
The sum of two subsets was defined by
and the scalar multiple by
for real numbers λ. One may rewrite the definition of the sum in the form