On Dec 21, 9:15 am, WM <mueck...@rz.fh-augsburg.de> wrote: > On 21 Dez., 14:23, "Dik T. Winter" <Dik.Win...@cwi.nl> wrote: > > > > > > > > Right, he uses a convention that is no longer used. > > > > > > Wrong, it is used presently, for instance by myself. > > > But you are not a mathematician. > > Do you think so? I studied mathematics and a university council > appointed me to teach mathematical lessons. Have you better insights > than they?