all the exceptional cases, but concrete constructions came later. As A. J. Coleman says, "He exhibited the characteristic equation of the Weyl group when Weyl was 3 years old and listed the orders of the Coxeter transformation 19 years before Coxeter was born." Selected works Work on non-Euclidean geometry Work on transformation groups See also Killing equation Killing form Killing–Hopf theorem Killing horizon Killing spinor Killing tensor Killing vector field Levi decomposition G2 (mathematics) Root system References External links 19th-century German mathematicians 20th-century German mathematicians 1847 births 1923 deaths Academic staff of the University of Münster People from Siegen-Wittgenstein