strictly upper triangular matrix

A strictly is an upper triangular matrix which has $0$ on the main diagonal. Similarly a strictly lower triangular matrix is a lower triangular matrix which has $0$ on the main diagonal. i.e.

\begin{bmatrix}0&a_{12}&a_{13}&\cdots&a_{1n}\\ 0&0&a_{23}&\cdots&a_{2n}\\ 0&0&0&\cdots&a_{3n}\\ \vdots&\vdots&\vdots&\ddots&\vdots\\ 0&0&0&\cdots&0\end{bmatrix}

A strictly lower triangular matrix is of the form

\begin{bmatrix}0&0&0&\cdots&0\\ a_{21}&0&0&\cdots&0\\ a_{31}&a_{32}&0&\cdots&0\\ \vdots&\vdots&\vdots&\ddots&\vdots\\ a_{n1}&a_{n2}&a_{n3}&\cdots&0\end{bmatrix}

Title	strictly upper triangular matrix
Canonical name	StrictlyUpperTriangularMatrix
Date of creation	2013-03-22 13:42:15
Last modified on	2013-03-22 13:42:15
Owner	Daume (40)
Last modified by	Daume (40)
Numerical id	8
Author	Daume (40)
Entry type	Definition
Classification	msc 15-00
Synonym	supertriangular
Defines	strictly lower triangular matrix