An Extension of a Result by Steinberg towards a Chevalley Basis Algorithm
نویسنده
چکیده
Let L be the Lie algebra of a simple algebraic group defined over F and let H be a split Cartan subalgebra of L. Let R = (X,Φ, Y,Φ∨) be the root datum of L, so that H = Y ⊗ F, and let 〈·, ·〉 : Φ × Φ∨ 7→ Z be the corresponding bilinear form. This bilinear form induces a linear form on the roots of L by defining α : h 7→ P i〈α, yi〉ti, where h = P i yi⊗ ti. Given a root α, we define the multiplicity of α in L to be the number of β ∈ Φ such that α = β. For R of adjoint type, Steinberg gave an overview of the cases where multiplicities greater than 1 occur. In this paper we give a complete overview of these cases, for R of any isogeny type.
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تاریخ انتشار 2008