Paul Gruner, Graphical representation of the four-dimensional space-time universe
“ To develop the phenomena of the theory of relativity, it is useful to measure time by the path traveled by light , being the speed of light equal to unity. Also it is best to choose a non-orthogonal system of coordinates as "subspace" ”
Paul Gruner, Graphical representation of the four-dimensional space-time universe
“ Taking into account these remarks it is easy to directly construct wavelengths and frequencies of undulatory motion in both systems; one exactly obtains the expressions given by Einstein, whose deductions thereby receive a new geometric confirmation. ”
