[Lecture] Local and 2-local derivations and automorphisms of Octonian algebras

Feb. 09, 2023

The talk is devoted to description of local and 2-local derivations (respectively, automorphisms) on octonian algebras. We shall give a general form of local derivations on the octonion algebra O(F) over a field F with zero characteristic. This description implies that the space of all local derivations on O(F) when equipped with Lie bracket is isomorphic to the Lie algebra so7 O(F) of all real skew-symmetric 7 × 7-matrices over F. At the same time the Lie algebra of all derivations are isomorphic to the exceptional Lie algebra g2(F). It follows that the octonion algebra O(F) and Malcev algebra M7(F) over the field F are simple non associative algebras which admit pure local derivations, that is, local derivations which are not derivation.

Further we consider 2-local derivations on the octonion algebra O(F) over an algebraically closed field F and prove that every 2-local derivation on O(F) is a derivation. But for the field R of real numbers 2-local derivations on the octonian algebra O(R) form a Lie algebra which is essentially larger than the Lie algebra g2(R) of derivations. we apply these results to problems for the simple 7-dimensional Malcev algebra. We shall give a general form of local automorphisms on the octonion algebra O(F). This description implies that the group of all local automorphisms on O(F) is isomorphic to the group O7(F) of all orthogonal 7 × 7-matrices over F, and it is essentially larger than the group of all automorphisms.

We also consider 2-local automorphisms on the octonion algebra O(F) over an algebraically closed field F and prove that every 2-local automorphism on O(F) is an automorphism. At the same time the group of 2-local automorphisms of O(R) is larger than the group of automorphisms of O(R). As a corollary we obtain descriptions of local and 2-local automorphisms of seven dimensional simple Malcev algebra.

Shavkat Ayupov is the Director of V.I. Romanovskiy Institute of Mathematics, Uzbekistan Academy of Sciences. His field of scientific interest include Theory of Operator Algebras and Quantum Probability, Structure theory of Non-associative algebras (Jordan, Lie, Leibniz, etc.). He is the authors of several monograph devoted to Real and Jordan structures on Operator Algebras, also to the structure theory of Leibniz algebras. Sh. Ayupov is a Member of Uzbekistan Academy of Sciences (since 1995), Fellow of TWAS (The World Academy of Sciences) (since 2003), Senior Associate of ICTP (International Centre for Theoretical Physics) (2008 – 2013), Guest Professor of Sichuan University (Chengdu, China) (2015-2021). He is the Managing Editor of Uzbek Mathematical Journal and editor of “Advances in Operator Theory”.

In 2017, he was awarded the State Prize of the first degree in the field of Science and Technology of the Republic of Uzbekistan.