Toupin, Daniel: Why String Theory Works: Division Algebras, Celestial Holography, and the Misidentification of the Fundamental Degrees of Freedom

We prove that the computational successes of string theory are consequences of two mathematical structures: the four normed division algebras and the axioms of two-dimensional conformal field theory. Eight results are established. (1) The Green-Schwarz critical dimensions D in {3,4,6,10} are classified by normed division algebras via the Hurwitz theorem. (2) The Veneziano amplitude and the celestial MHV coefficient are both uniquely fixed by Haar measure on (R+,x). (3) Shadow symmetry Delta 2-De