Divisible subgroups of Brauer groups and trace forms of central simple algebras.
We give an automata-theoretic description of the algebraic closure of the rational function field over a finite field , generalizing a result of Christol. The description occurs within the Hahn-Mal’cev-Neumann field of “generalized power series” over . In passing, we obtain a characterization of well-ordered sets of rational numbers whose base expansions are generated by a finite automaton, and exhibit some techniques for computing in the algebraic closure; these include an adaptation to positive...
We study whether the projective and injective properties of left -modules can be implied to the special kind of left -modules, especially to the case of inverse polynomial modules and Laurent polynomial modules.
A ring is called a left APP-ring if the left annihilator is right -unital as an ideal of for any element . We consider left APP-property of the skew formal power series ring where is a ring automorphism of . It is shown that if is a ring satisfying descending chain condition on right annihilators then is left APP if and only if for any sequence of elements of the ideal
Let be a ring. We recall that is called a near pseudo-valuation ring if every minimal prime ideal of is strongly prime. Let now be an automorphism of and a -derivation of . Then is said to be an almost -divided ring if every minimal prime ideal of is -divided. Let be a Noetherian ring which is also an algebra over ( is the field of rational numbers). Let be an automorphism of such that is a -ring and a -derivation of such that for all . Further, if for any...
If is a prime ring such that is not completely reducible and the additive group is not complete, then is slender.
Let be a commutative ring and a given multiplicative set. Let be a strictly ordered monoid satisfying the condition that for every . Then it is shown, under some additional conditions, that the generalized power series ring is -Noetherian if and only if is -Noetherian and is finitely generated.