  A converse to Lie's theorem for Leibniz algebras is found and generalized.
The result is used to find cases in which the generalized property, called
triangulable, is 2-recognizeable; that is, if all 2-generated subalgebras are
triangulable, then the algebra is also. Triangulability joins solvability,
supersolvability, strong solvability, and nilpotentcy as a 2-recognizeable
property for classes of Leibniz algebras.
