Linear mapping/Trigonalizable/Characterizations/Method/Remark

{{ Mathematical text/Remark |Text= The method to find an invariant flag, which is described in the proof of the implication (4) ${\displaystyle {}\Rightarrow }$ (2) of fact and which rests on fact, is constructive. If the restriction {{mathl|term= \varphi{{|}}_{ U_i } |pm=}} to some invariant linear subspace ${\displaystyle {}U_{i}}$ already constructed does not have an eigenvalue, then we know that the linear mapping is not trigonalizable. |Textform=Remark |Category= }}