On finite homomorphic images of the multiplicative group of a division algebra.
On free subgroups of units in quaternion algebras
It is well known that for the ring H(ℤ) of integral quaternions the unit group U(H(ℤ) is finite. On the other hand, for the rational quaternion algebra H(ℚ), its unit group is infinite and even contains a nontrivial free subgroup. In this note (see Theorem 1.5 and Corollary 2.6) we find all intermediate rings ℤ ⊂ A ⊆ ℚ such that the group of units U(H(A)) of quaternions over A contains a nontrivial free subgroup. In each case we indicate such a subgroup explicitly. We do our best to keep the arguments...
On free subgroups of units in quaternion algebras II
Let A ⊆ ℚ be any subring. We extend our earlier results on unit groups of the standard quaternion algebra H(A) to units of certain rings of generalized quaternions H(A,a,b) = ((-a,-b)/A), where a,b ∈ A. Next we show that there is an algebra embedding of the ring H(A,a,b) into the algebra of standard Cayley numbers over A. Using this embedding we answer a question asked in the first part of this paper.
On Galois projective group rings.
On generalized periodic-like rings.
On group rings of ordered groups
On groups of similitudes in associative rings
Let be an associative ring with 1 and the multiplicative group of invertible elements of . In the paper, subgroups of which may be regarded as analogues of the similitude group of a non-degenerate sesquilinear reflexive form and of the isometry group of such a form are defined in an abstract way. The main result states that a unipotent abstractly defined similitude must belong to the corresponding abstractly defined isometry group.
On infinite periodic rings.
On isomorphic commutative group algebras of Abelian groups with -projective quotients.
On Jordan ideals and derivations in rings with involution
Let be a -torsion free -prime ring, a derivation which commutes with and a -Jordan ideal and a subring of . In this paper, it is shown that if either acts as a homomorphism or as an anti-homomorphism on , then or . Furthermore, an example is given to demonstrate that the -primeness hypothesis is not superfluous.
On Jordan ideals and left -derivations in prime rings.
On Lie ideals with generalized derivations.
On McCoy condition and semicommutative rings
Let be a ring and an endomorphism of . We give a generalization of McCoy’s Theorem [ Annihilators in polynomial rings, Amer. Math. Monthly 64 (1957), 28–29] to the setting of skew polynomial rings of the form . As a consequence, we will show some results on semicommutative and -skew McCoy rings. Also, several relations among McCoyness, Nagata extensions and Armendariz rings and modules are studied.
On modules in which idempotent reducts form a chain
On near-ring ideals with -derivation
Let be a -prime left near-ring with multiplicative center , a -derivation on is defined to be an additive endomorphism satisfying the product rule for all , where and are automorphisms of . A nonempty subset of will be called a semigroup right ideal (resp. semigroup left ideal) if (resp. ) and if is both a semigroup right ideal and a semigroup left ideal, it be called a semigroup ideal. We prove the following results: Let be a
On nearrings with derivation.
On periodic rings.
On prime near-rings with generalized derivation.
On products of singular elements
On rings satisfying certain polynomial identities.