Hadwiger's theorem characterizes the Euler characteristic as the unique (up to scalar multiplication) translation-invariant, finitely additive, not-necessarily-nonnegative set function defined on finite unions of compact convex sets in that is "homogeneous of degree 0".
Hadwiger's theorem characterizes the Euler characteristic as the unique (up to scalar multiplication) translation-invariant finitely additive, not-necessarily-nonnegative set f.unction defined on finite unions of compact convex sets in, that is "homogeneous of degree 0"