Abstract
It is well known that for a quaternion algegra, the anisotropy of its norm form determines if the quaternion algebra is a division algebra. In case of biquaternio algebra, the anisotropy of the associated Albert form (as defined in [LLT]) determines if the biquaternion algebra is a division ring. In these situations, the norm forms and the Albert forms are quadratic forms over the center of the quaternion algebras; and they are strongly related to the algebraic structure of the algebras. As it turns out, there is a natural way to associate a tensor product of quaternion algebras with a form such that when the involution is orthogonal, the algebra is a Baer ordered *-field iff the associated form is anisotropic.
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References
[C1] T. Craven,Approximation properties for orderings on *-fields, Transactions of the American Mathematical Society310 (1988), 837–850.
[C2] T. Craven,Orderings, valuations and hermitian forms over *-fields, Proceedings of Symposia in Pure Mathematics58 (1995), 149–160.
[Co] P. M. Cohn,Quadratic extensions of skew fields, Proceedings of the London Mathematical Society (3)11 (1961), 531–556.
[CW] M. Chacron and A. Wadsworth,On decomposing c-valued division rings, Journal of Algebra134 (1990), 182–208.
[H1] S. Holland Jr.,Orderings and square roots in *-fields, Journal of Algebra46 (1977), 207–219.
[H2] S. Holland Jr.,*-valuations and ordered *-fields, Transactions of the American Mathematical Society262 (1980), 219–243.
[L1] T. Y. Lam,The Algebraic Theory of Quadratic Forms, Benjamin/Cummings, Reading, MA, 1980.
[L2] T. Y. Lam,Orderings, Valuations and Quadratic Forms, Conference Board of the Mathematical Sciences, American Mathematical Society, 1983.
[LLT] T. Y. Lam, D. B. Leep and J.-P. Tignol,Biquaternion algebras and quartic extensions, Publications Mathématiques de l’Institut des Hautes Études Scientifiques77 (1993), 63–102.
[Le1] K. H. Leung,Weak *-orderings on *-fields, Journal of Algebra156 (1993), 157–177.
[Le2] K. H. Leung,Strong approximation property for Baer orderings on *-fields, Journal of Algebra165 (1994), 1–22.
[M] P. Morandi,The Henselization of a valued division algebra, Journal of Algebra122 (1989), 232–243.
[P] A. Prestel,Lectures on Formally Real Fields, Lecture Notes in Mathematics1093, Springer-Verlag, Berlin, 1985.
[S] W. Scharlau,Quadratic and Hermitian Forms, A Series of Comprehensive Studies in Mathematics270, Springer-Verlag, Berlin, 1985.
[TW] J.-P. Tignol and A. R. Wadsworth,Totally ramified valuations on finitedimensional division algebras, Transactions of the American Mathematical Society302 (1987), 223–249.
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Leung, K.H. Forms and Baer ordered *-fields. Isr. J. Math. 116, 1–19 (2000). https://doi.org/10.1007/BF02773209
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DOI: https://doi.org/10.1007/BF02773209