The Joly–Becker theorem for –orderings
We prove the –version of the Joly–Becker theorem: a skew field admits a –ordering of level iff it admits a –ordering of level for some (resp. all) odd . For skew fields with an imaginary unit and fields stronger results are given: a skew field with imaginary unit that admits a –ordering of higher level also admits a –ordering of level . Every field that admits a –ordering of higher level admits a –ordering of level or