@article{1600945,
abstract = {The trace form of a central simple algebra of degree 4. Let k be a field of characteristic different from 2 containing a primitive 4-th root of unity. We show that the trace quadratic form of any central simple k-algebra A of degree 4 decomposes in the Witt group of k as the sum of a 2-fold Pfister form q(2) and a 4-fold Pfister form q(4) which are uniquely determined by A. The form q2 is the norm form of the quaternion algebra Brauer-equivalent to A circle times(k) A, and q(4) is hyperbolic if and only if A is a symbol algebra. To cite this article: M. Rost et al., C R. Acad. Sci. Paris, Ser. 1342 (2006). (c) 2005 Academie des sciences. Publie par Elsevier SAS. Tons droits reserves.},
author = {Rost, Markus and Serre, Jean-Pierre and Tignol, Jean-Pierre},
issn = {1631-073X},
journal = {COMPTES RENDUS MATHEMATIQUE},
number = {2},
pages = {83--87},
publisher = {Elsevier},
title = {{ La forme trace d'une algèbre simple centrale de degré 4}},
doi = {10.1016/j.crma.2005.11.002},
volume = {342},
year = {2006},
}