Abstract
Okubo algebras form an important class of nonunital composition algebras of dimension 8. Contrary to what happens for unital composition algebras, they are not determined by their multiplicative norms. Okubo algebras with isotropic norm are characterized here by the existence of a special grading. In the split case, and under some restrictions on the ground field, the automorphism group of the most symmetric of these gradings is the projective unitary group \(\textrm{PU}(3,2^2)\), whose structure is showcased by the grading.
Supported by grant MTM2017-83506-C2-1-P (AEI/FEDER, UE), by grant PID2021-123461NB-C21, funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”, and by grants E22_17R and E22_20R (Gobierno de Aragón, Grupo de investigación “Álgebra y Geometría”).
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References
Chernousov, V., Elduque, A., Knus, M.-A., Tignol, J.-P.: Algebraic groups of type \(D_4\), triality, and composition algebras. Doc. Math. 18, 413–468 (2013)
Elduque, A.: Symmetric composition algebras. J. Algebra 196(1), 282–300 (1997)
Elduque, A.: Okubo Algebras and Twisted Polynomials, Recent Progress in Algebra (Taejon/Seoul, 1997), pp. 101–109, Contemp. Math. 224, Amer. Math. Soc., Providence, RI (1999)
Elduque, A.: Gradings on symmetric composition algebras. J. Algebra 322(10), 3542–3579 (2009)
Elduque, A.: Order \(3\) elements in \(G_2\) and idempotents in symmetric composition algebras. Canad. J. Math. 70(5), 1038–1075 (2018)
Elduque, A.: Composition algebras. In: Abdenacer, M. (ed.) Algebra and Applications I: Non-associative Algebras and Categories, Chapter 2, pp. 27–57. Sciences-Mathematics, ISTE-Wiley, London (2021)
Elduque, A., Kochetov, M.: Gradings on Simple Lie Algebras, Mathematical Surveys and Monographs, vol. 189. American Mathematical Society, Providence, RI (2013)
Elduque, A., Myung, H.C.: Flexible composition algebras and Okubo algebras. Comm. Algebra 19(4), 1197–1227 (1991)
Elduque, A., Myung, H.C.: On flexible composition algebras. Comm. Algebra 21(7), 2481–2505 (1993)
Elduque, A., Pérez-Izquierdo, J.M.: Infinite-dimensional quadratic forms admitting composition. Proc. Amer. Math. Soc. 125(8), 2207–2216 (1997)
Grove, L.C.: Classical Groups and Geometric Algebra, Graduate Studies in Mathematics 39. American Mathematical Society, Providence, Rhode Island (2002)
Hesselink, W.H.: Special and pure gradings of Lie algebras. Math. Z. 179(1), 135–149 (1982)
Knus, M.-A., Merkurjev, A., Rost, M., Tignol, J.-P.: The Book of Involutions, American Mathematical Society Colloquium Publications 44. American Mathematical Society, Providence, RI (1998)
Okubo, S.: Pseudo-quaternion and pseudo-octonion algebras. Hadronic J. 1(4), 1250–1278 (1978)
Okubo, S., Osborn, J.M.: Algebras with nondegenerate associative symmetric bilinear forms permitting composition II. Comm. Algebra 9(20), 2015–2073 (1981)
Pierce, R.S.: Associative Algebras, Graduate Texts in Mathematics 88. Springer-Verlag, New York (1982)
Smith, J.D.H., Vojtěchovský, P.: Okubo quasigroups. Doc. Math. 27, 535–580 (2022)
Springer, T.A., Veldkamp, F.D.: Octonions, Jordan Algebras and Exceptional Groups. Springer Monographs in Mathematics, Springer-Verlag, Berlin (2000)
Zhevlakov, K.A., Slin’ko, A.M., Shestakov, I.P., Shirshov, A.I.: Rings that are nearly associative. Academic Press, New York (1982)
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Elduque, A. (2023). Okubo Algebras with Isotropic Norm. In: Albuquerque, H., Brox, J., Martínez, C., Saraiva, P. (eds) Non-Associative Algebras and Related Topics. NAART 2020. Springer Proceedings in Mathematics & Statistics, vol 427. Springer, Cham. https://doi.org/10.1007/978-3-031-32707-0_18
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