Overlap graph for pattern , CTTTCGC, TACCACA}. Nodes are the elements of . The node with the index number “1” corresponds to ε, it is the root. The left edges are shown by continuous straight lines, right edges are shown by dashed lines and deep edges are shown by double lines. Each left edge (l p r e d(w),w), where , is labeled with B a c k(w). For example, edge (2,3) corresponding to the pair of overlaps (A, ACA) is labeled with B a c k(ACA)=CA. A deep edge (w,r) corresponds to equivalence class . The right edges (w,r p r e d(w)) are not labeled.