Resumen de On Valuations, Places and Graded Rings Associated to *-Orderings
We study natural *-valuations, *-places and graded *-rings associated with *-ordered rings. We prove that the natural *-valuation is always quasi-Ore and is even quasi-commutative (i.e., the corresponding graded *-ring is commutative), provided the ring contains an imaginary unit. Furthermore, it is proved that the graded *-ring is isomorphic to a twisted semigroup algebra. Our results are applied to answer a question of Cimpric regarding *-orderability of quantum groups
