Additive maps preserving products equal to fixed elements on Cayley-Dickson algebrasMacedo Ferreira, Bruno Leonardo; Julius, Hayden
doi: 10.1080/00927872.2024.2431889pmid: N/A
Abstract– In this paper, we study additive maps f : A → A on an alternative Cayley-Dickson algebra A satisfying the product preserving property: f ( x ) f ( y ) = m whenever xy = k, where k and m are constant elements of A . We prove that f may be written as a multiple of a Jordan homomorphism. Unlike in the associative case, Jordan homomorphisms of strictly alternative division rings need not be homomorphisms or anti-homomorphisms, but we provide necessary and sufficient conditions for this to occur. We then extend these ideas to split alternative Cayley-Dickson algebras of characteristic not 2 and present some open questions when k or m is noninvertible. The final section handles the problem k = m = 0 and generalizes to biadditive maps that preserve the zero product.
Division quaternion algebras over some cyclotomic fieldsSavin, Diana
doi: 10.1080/00927872.2024.2448237pmid: N/A
Abstract Let p 1, p 2 be two distinct prime integers, let n be a positive integer, n ≥ 3 and let ξn be a primitive root of order n of the unity. In the 3rd section of this paper we obtain a complete characterization for a quaternion algebra H ( p 1 , p 2 ) to be a division algebra over the nth cyclotomic field Q ( ξ n ) , when n ∈ { 3 , 4 , 6 , 7 , 8 , 9 , 11 , 12 } and we also obtain a characterization for a quaternion algebra H ( p 1 , p 2 ) to be a division algebra over the nth cyclotomic field Q ( ξ n ) , when n ∈ { 5 , 10 } . In the 4th section we obtain a complete characterization for a quaternion algebra H Q ( ξ n ) ( p 1 , p 2 ) to be a division algebra, when n = l k , with l a prime integer, l ≡ 3 (mod 4) and k a positive integer. In the last section of this article we obtain a complete characterization for a quaternion algebra H Q ( ξ l ) ( p 1 , p 2 ) to be a division algebra, when l is a Fermat prime number.
Revisiting global Perinormality in a generalized D + M constructionPal, Sourav; Singh, Ravinder
doi: 10.1080/00927872.2024.2433081pmid: N/A
Abstract Klawa proved that global perinormality is preserved in a pullback construction which encompasses a classical D + M construction (Klawa H. (2023). Global perinormality in a generalized D + M construction. Communications in Algebra, 51:3015–3019). More precisely, if ( T , M ) is a local domain, with the residue field k, and an integral domain D whose quotient field is k, Klawa proved that if the pullback D × k T is globally perinormal, then D and T are also globally perinormal. We generalize this result by dropping the localness assumption from T. Several additional results, which are of independent interest, are also proved.
2-Local derivations of the n-th Schrödinger algebraYao, Lulu; Yu, Yalong
doi: 10.1080/00927872.2024.2433682pmid: N/A
Abstract Let K be a field, L a Lie algebra over K . A 2-Local derivation on L is a map (not linear in general) Δ : L → L which satisfies that for every x , y ∈ L , there exists a derivation D x , y (depending on x, y) on L such that Δ ( x ) = D x , y ( x ) and Δ ( y ) = D x , y ( y ) . In this article, we prove that any 2-local derivation of the n-th Schrödinger algebra s c h n is a derivation.