Imaginary elements in geometryKarl von Staudt found a brilliant way to visualize imaginary geometric points, lines and planes, and Felix Klein simplified and extended his method. In this book imaginary elements appear as Klein movements in our real space. Apart from its mathematical importance, these movements may be seen as an alternative for the remarkable occurrences of complex numbers in physics, viz. quantum physics. von L. A. D. de Boer; Herausgegeben von Mathematisch