Submission date: 22 March 2018

Abstract:

A generalization of von Staudt's theorem that every permutation of the projective line that preserves harmonic quadruples is a projective semilinear map is given. It is then concluded that any proper supergroup of permutations of the projective semilinear group over an algebraically closed field of transcendence degree at least 1 is 4-transitive.

Mathematics Subject Classification:

Keywords and phrases:

Full text arXiv 1803.08520: pdf, ps.