Currently, I am looking at matrix $A$ and I am wondering if it is totally unimodular (TU).
I would like to clarify if I truncate matrix $A$ such that the right hand side of the matrix is an identity matrix, then can I say that it is TU? Otherwise, how should we be explaining TU for this matrix?
Thanks for your help!
This matrix is clearly not totally unimodular. The top-left entry is $2$. For TU matrices only entries from $\{-1,0,1\}$ are allowed.