For example, in Figure 17, these are the hyperedges [x, ], [y, ], and [u, ], which are covered by {e(x, 1), e(x, 2), e(y, 1), e(y, 2), e(u, 1), e(u, 2)}.
assume finally that b is not the root of T. If cont T (b) = {v 1 , .