“…As in Lemma 6.1 we find ttrails p 1 and p 2 from v j to v i such that s r , p 1 Thus the elements of B ′ (V , A) are, by abuse of notation, such elements of W (V E, A), which take 0 value of every edge of G. For the case of A = Z 2 this would be identical to describing the consistent marked (vertex-signed) graphs, which were studied and characterized in [1,2,8,11,13,17]. In [12] some relations between consistent marked graphs and balanced signed graphs are studied.…”