Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

If $L$ is a lower triangular matrix of ones, does the following matrix have a special name?

$$A = \left(\begin{matrix}L & -L \\ -L & L \end{matrix}\right)$$

share|improve this question
4  
It might be $\pmatrix{1 &-1\\ -1 &1}\otimes L$. ($\otimes$ denotes the Kronecker product) –  user13838 Oct 9 '11 at 19:25
    
What does this have to do with graph theory? –  anon Oct 9 '11 at 22:19
    
well I had it written as part of a solution to an LP formulation of a flow network, so perhaps graph theorists could have a better idea on what it's called. –  István Oct 10 '11 at 8:56
add comment

1 Answer 1

It's a special type of "block matrix". Or, as user13838 points out, it can be described as a Kronecker product (or direct product).

(Or, you could just call it $A$.)

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.