On distant-isomorphisms of projective lines

Aequationes mathematicae - Tập 69 - Trang 146-163 - 2005
Andrea Blunck1, Hans Havlicek2
1Fachbereich Mathematik, Universität Hamburg, Hamburg, Germany
2Institut für Diskrete Mathematik und Geometrie, Technische Universität, Wien, Austria

Tóm tắt

We determine all distant-isomorphisms between projective lines over semilocal rings. In particular, for those semisimple rings that do not have a simple component which is isomorphic to a field, every distant isomorphism arises from a Jordan isomorphism of rings and a projectivity. We show this by virtue of a one-one correspondence linking the projective line over a semisimple ring with a Segre product of Grassmann spaces.