scholarly journals An action of the automorphism group of a commutative ring on its Brauer group

1981 ◽  
Vol 97 (2) ◽  
pp. 327-338 ◽  
Author(s):  
Frank DeMeyer
1998 ◽  
Vol 41 (3) ◽  
pp. 359-367 ◽  
Author(s):  
Fred Van Oystaeyen ◽  
Yinhuo Zhang

AbstractLet H be a faithfully projective Hopf algebra over a commutative ring k. In [8, 9] we defined the Brauer group BQ(k, H) of H and an homomorphism π from Hopf automorphism group AutHopf(H) to BQ(k,H). In this paper, we show that the morphism π can be embedded into an exact sequence.


2007 ◽  
Vol 17 (03) ◽  
pp. 527-555 ◽  
Author(s):  
YOU'AN CAO ◽  
DEZHI JIANG ◽  
JUNYING WANG

Let L be a finite-dimensional complex simple Lie algebra, Lℤ be the ℤ-span of a Chevalley basis of L and LR = R⊗ℤLℤ be a Chevalley algebra of type L over a commutative ring R. Let [Formula: see text] be the nilpotent subalgebra of LR spanned by the root vectors associated with positive roots. The aim of this paper is to determine the automorphism group of [Formula: see text].


2020 ◽  
Vol 27 (03) ◽  
pp. 587-598
Author(s):  
M’hammed El Kahoui ◽  
Najoua Essamaoui ◽  
Mustapha Ouali

Let R be a commutative ring with unity and SAn(R) be the group of volume-preserving automorphisms of the polynomial R-algebra R[n]. Given a proper ideal 𝔞 of R, we address in this paper the question of whether the canonical group homomorphism SAn(R) → SAn(R/𝔞) is surjective. As an application, we retrieve and generalize, in a unified way, several known results on residual coordinates in polynomial rings.


1976 ◽  
Vol 28 (3) ◽  
pp. 533-552 ◽  
Author(s):  
Morris Orzech

Beginning with Wall's introduction [19] of Z2-graded central simple algebras over a field K, a number of related generalizations of the Brauer group have been proposed. In [16] the field K was replaced by a commutative ring R, building upon the theory developed in [1]. The concept of a G-graded central simple K-algebra (G an abelian group) was first defined in [12]; this work and that of [16] was subsequently unified in [6] and [7] via the construction and computation of the graded Brauer group Bφ﹛R, G) (φ a bilinear form from G X G to U(R), the units of R).


1980 ◽  
Vol 3 (2) ◽  
pp. 237-245 ◽  
Author(s):  
George Szeto

LetBbe a commutative ring with1, andG(={σ})an automorphism group ofBof order2. The generalized quaternion ring extensionB[j]overBis defined byS. Parimala andR. Sridharan such that (1)B[j]is a freeB-module with a basis{1,j}, and (2)j2=−1andjb=σ(b)jfor eachbinB. The purpose of this paper is to study the separability ofB[j]. The separable extension ofB[j]overBis characterized in terms of the trace(=1+σ)ofBover the subring of fixed elements underσ. Also, the characterization of a Galois extension of a commutative ring given by Parimala and Sridharan is improved.


Author(s):  
Benson Farb ◽  
R. Keith Dennis

2012 ◽  
Vol 2012 ◽  
pp. 1-12
Author(s):  
Xing Tao Wang ◽  
Lei Zhang

LetCl+1(R)be the2(l+1)×2(l+1)matrix symplectic Lie algebra over a commutative ringRwith 2 invertible. Thentl+1CR  =  {m-1m-20-m-1T ∣ m̅1is anl+1upper triangular matrix,m̅2T=m̅2,  over  R}is the solvable subalgebra ofCl+1(R). In this paper, we give an explicit description of the automorphism group oftl+1(C)(R).


1960 ◽  
Vol 97 (3) ◽  
pp. 367-367 ◽  
Author(s):  
Maurice Auslander ◽  
Oscar Goldman

2013 ◽  
Vol 12 (06) ◽  
pp. 1250224
Author(s):  
B. FEMIĆ

With the motivation of giving a more precise estimation of the quantum Brauer group of a Hopf algebra H over a field k we construct an exact sequence containing the quantum Brauer group of a Hopf algebra in a certain braided monoidal category. Let B be a Hopf algebra in [Formula: see text], the category of Yetter–Drinfel'd modules over H. We consider the quantum Brauer group [Formula: see text] of B in [Formula: see text], which is isomorphic to the usual quantum Brauer group BQ(k; B ⋊ H) of the Radford biproduct Hopf algebra B ⋊ H. We show that under certain symmetricity condition on the braiding in [Formula: see text] there is an inner action of the Hopf automorphism group of B on the former. We prove that the subgroup [Formula: see text] — the Brauer group of module algebras over B in [Formula: see text] — is invariant under this action for a family of Radford biproduct Hopf algebras. The analogous invariance we study for BM(k; B ⋊ H). We apply our recent results on the latter group and generate a new subgroup of the quantum Brauer group of B ⋊ H. In particular, we get new information on the quantum Brauer groups of some known Hopf algebras.


1980 ◽  
Vol 32 (6) ◽  
pp. 1523-1524 ◽  
Author(s):  
Morris Orzech

Let R be a commutative ring, G a finite abelian group. Let A be an R-algebra which is graded by G (i.e. A = Σ⊕σ∈GAσ, where AσAτ ⊂ Aστ for σ, τ in G) and for which A1 is an R-module of finite type. In Remark 4.1 (a) of [1] we asserted that under these hypotheses if u is in A and u + pA is homogeneous in A/pA for each maximal ideal p of R then u is homogeneous in A. We used this assertion for u a unit in A such that a → uau–1 is a grading-preserving homomorphism. K. Ulbrich has kindly pointed out a counterexample to the assertion: R = Z/4Z, G = {1, σ};, u = 2σ + 1, p = 2R. Proposition 4.2 of [1] uses the erroneous result and is in turn invoked later in the paper.


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