In Wikipedia It is written that
Jordan canonical form is an upper triangualr matrix of a particular form called a Jordan matrix representing a linear operator on a finite dimensional vector space with respect to some basis
My confusion :why is lower triangular matrix not mentioned in the Jordan normal form definition ?
My thinking : I can also construct lower triangular matrix in the same pattern
see the diagram below
Every matrix is simlar to its transponse, so a lower triangular Jordan block would be similar to an upper triangular Jordan block. I recall reading a linear algebra book (I think Serge Lang's) where the Jordan form was lower triangular. It's all a matter of reversing the order of the cyclic (sub-)basis.