Csaba Vincze (2013)
University of Debrecen
Excercise 5.2.1 Prove that the kernel of D is convex.
Excercise 5.2.2 Find the kernels of the following shapes in the plane.
Excercise 5.2.3 Prove that the points
in the proof of Krasnosselsky's theorem is not collinear.
Hint. In case of collinear points we have that p(0)=v(0) and z=z(0). Therefore H(0) separates the convex hull of B(p(0)) and u which is obviously a contradiction.