Hilbert's twenty-third problem [SEP] named after
Hilbert's twenty-third problem
Hilbert's twenty-third problem is the last of Hilbert problems set out in a celebrated list compiled in 1900 by David Hilbert. In contrast with Hilbert's other 22 problems, his 23rd is not so much a specific "problem" as an encouragement towards further development of the calculus of variations. His statement of the problem is a summary of the state-of-the-art (in 1900) of the theory of calculus of variations, with some introductory comments decrying the lack
Schläfli orthoscheme
In geometry, Schläfli orthoscheme is a type of simplex. They are defined by a sequence of edges formula_1 that are mutually orthogonal. These were introduced by Ludwig Schläfli, who called them "orthoschemes" and studied their volume in the Euclidean, Lobachevsky and the spherical geometry. H. S. M. Coxeter later named them after Schläfli. J.-P. Sydler and Børge Jessen studied them extensively in connection with Hilbert's third problem.
Orthoschemes, also called path-simplices in the applied mathematics literature, are a special case of