Nullspace of a transpose incidence matrix
Recall the definition of the arc-node incidence matrix of a network.
By definition, the arc-node incidence matrix 
, we have 
, where 
is the vector of ones (in 
). Hence is in the nullspace of 
.
Recall the definition of the arc-node incidence matrix of a network.
By definition, the arc-node incidence matrix , we have , where is the vector of ones (in ). Hence is in the nullspace of .