Invariant intrinsic Finsler metrics on homogeneous spaces and strong subalgebras of Lie algebras

We study the algebraic conditions for all intrinsic metrics to be Finsler on a homogeneous space. These conditions were firstly found by Berestovskii in terms of Lie algebras and their subalgebras (the corresponding subalgebras will be called strong).
We obtain a description of the structure of strong subalgebras in semisimple solvable Lie algebras as well as Lie algebras of a general form. We also obtain some results on maximal strong subalgebras and Lie algebras with at least one strong subalgebra.