Upper triangular need to be interpreted as possessing only zero entries underneath the most crucial diagonal, which starts off within the higher still left corner. Illustration[edit] A A A B A C A D A E A F A G A H A I A J A K A http://landengqyhn.educationalimpactblog.com/17668713/considerations-to-know-about-how-t-u-an-l-b-d