Abstract
By analyzing the dimensions of the quantities I found what I called the main sequence. A column with respectively time, length, mass, momentum and energy. Because of symmetry I concluded that in this main sequence the number of quantities must be extended. And therefore that both the Minkowski metric and the relativistic energy-momentum equation had to be extended. They are combined into the 16-dimensional general metric. From this metric I developed an octonion model of gravity. The elements of the two opposite octonions involved are proportional imaginairy quantities. The physical equations have their origin in and are limited by this intrinsic structure of the quantities.
Peter van Gaalen