scholarly journals Composition of quadratic forms and tensor product of quaternion algebras

1985 ◽  
Vol 96 (2) ◽  
pp. 347-367 ◽  
Author(s):  
Sergey Yuzvinsky
1986 ◽  
Vol 28 (2) ◽  
pp. 227-228 ◽  
Author(s):  
P. Mammone ◽  
J. P. Tignol

In a recent paper [3], D. W. Lewis proposed the following conjecture. (The notation is the same as that in [2] and [3].)Conjecture. Let F be a field of characteristic not 2 and let a1, b1…, an, bn ∈ Fx. The tensor product of quaternion algebrasis a division algebra if and only if the quadratic form over Fis anisotropic.This equivalence indeed holds for n = 1 as is well known [2, Theorem 2.7], and Albert [1] (see also [4, §15.7]) has shown that it also holds for n = 2. The aim of this note is to provide counterexamples to both of the implications for n ≥ 3.


1988 ◽  
Vol 30 (1) ◽  
pp. 111-113
Author(s):  
P. Mammone

The purpose of this note is to generalize to fields of characteristic two the results obtained in [4]. We obtain necessary and sufficient conditions involving quadratic forms for certain tensor products of quaternion algebras to be division algebras.


2018 ◽  
Vol 111 (2) ◽  
pp. 135-143
Author(s):  
Karim Johannes Becher ◽  
Nicolas Grenier-Boley ◽  
Jean-Pierre Tignol

Author(s):  
J. H. H. Chalk ◽  
B. G. A. Kelly

SynopsisFor a class of Fuchsian groups, which includes integral automorphs of quadratic forms and unit groups of indefinite quaternion algebras, it is shown that the geometry of a suitably chosen fundamental region leads to explicit bounds for a complete set of generators.


2015 ◽  
Vol 14 (07) ◽  
pp. 1591001
Author(s):  
Adam Chapman

We show how the chain lemma for quaternion algebras over fields of F ≠ 2 and [Formula: see text] can be strengthened so that up to two slots are changed at a time.


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