Richard Brauer - Hypercomplex Numbers

Hypercomplex Numbers

Eduard Study had written an article on hypercomplex numbers for Klein's encyclopedia in 1898. This article was expanded for the French language edition by Henri Cartan in 1908. By the 1930s there was evident need to update Study’s article, and Richard Brauer was commissioned to write on the topic for the project. As it turned out, when Brauer had his manuscript prepared in Toronto in 1936, though it was accepted for publication, politics and war intervened. Nevertheless, Brauer kept his manuscript through the 40s, 50s, and 60s, and in 1979 it was published by Okayama University in Japan. It also appeared posthumously as paper #22 in the first volume of his Collected Papers. His title was "Algebra der hyperkomplexen Zahlensysteme (Algebren)". Unlike the articles by Study and Cartan, which were exploratory, Brauer’s article reads as a modern abstract algebra text with its universal coverage. Consider his introduction:

In the beginning of the 19th century, the usual complex numbers and their introduction through computations with number-pairs or points in the plane, became a general tool of mathematicians. Naturally the question arose whether or not a similar "hypercomplex" number can be defined using points of n-dimensional space. As it turns out, such extension of the system of real numbers requires the concession of some of the usual axioms (Weierstrass 1863). The selection of rules of computation, which cannot be avoided in hypercomplex numbers, naturally allows some choice. Yet in any cases set out, the resulting number systems allow a unique theory with regard to their structural properties and their classification. Further, one desires that these theories stand in close connection with other areas of mathematics, wherewith the possibility of their applications is given.

While still in Königsberg in 1929, Brauer published an article in Mathematische Zeitschrift "Über Systeme hyperkomplexer Zahlen" which was primarily concerned with integral domains (Nullteilerfrei systeme) and the field theory which he used later in Toronto.