  We consider the volume of a Boolean expression of some congruent balls about
a given system of centers in the $d$-dimensional Euclidean space. When the
radius $r$ of the balls is large, this volume can be approximated by a
polynomial of $r$, which will be computed up to an $O(r^{d-3})$ error term. We
study how the top coefficients of this polynomial depend on the set of the
centers. It is known that in the case of the union of the balls, the top
coefficients are some constant multiples of the intrinsic volumes of the convex
hull of the centers. Thus, the coefficients in the general case lead to
generalizations of the intrinsic volumes, in particular, to a generalization of
the mean width of a set. Some known results on the mean width, along with the
theorem on its monotonicity under contractions are extended to the "Boolean
analogues" of the mean width.
