# Does this matrix have a name?

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

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

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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

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 $A$.)

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