... define a multivariate polynomial that generalizes in a unified way the two-variable interlace polynomial defined by Arratia, Bollob´as and Sorkin on the onehand, and a one-variable variant of ... C, {b} and edges between A and C,b and C, b and A. It follows that N(G a , a) = N(G, a) and N(G a , b) = A ∪ B ∪ {a} . The local complementation at b toggles edges and loops in A, B, {a} and edgesbetween ... edgesbetween A and B, a and A, a and B. It follows that N((G a )b, a) = B ∪ C ∪ {b} and N((G a )b, b) = N(G a , b). The second local complementation at a toggles edges and loops in B, C, {b} and edges...