Die vierte Dimension. Mathematik und Wirklichkeit

The first part of this volume consists of a series of lectures on the then widely discussed problem in the cultural world regarding the real existence of a fourth dimension. A significant portion is dedicated to explanations of the geometry of four-dimensional bodies. The more extensive second part contains a compilation of questions and answers on topics such as projective geometry, the speed of light, flowing geometries between original and image, positive and negative numbers, imaginary and hyperimaginary numbers, the third law of Copernicus, and particularly the theory of relativity by Albert Einstein.