Hadwiger's conjecture for cap bodies

Abstract: Hadwiger's covering conjecture is that every $n$-dimensional convex body can be covered by at most $2^n$ of its smaller homothetic copies, with $2^n$ copies required only for affine images of $n$-cube. Convex hull of a ball and an external point is called a cap. The union of finitely many caps of a ball is a cap body if it is a convex set. In this note, we confirm the Hadwiger's conjecture for the class of cap bodies in all dimensions, bridging recently established cases of $n=3$ and large $n$. For $4\le n\le 15$, the proof combines a probabilistic technique with reduction to linear programming performed with computer assistance. For $n\ge 9$, we give an explicit bound on illumination number of cap bodies based on the same probabilistic technique but avoiding computer aid.