Fig. 4.

Planar projections of the simplex ${\mathrm{\Delta }}_2$ showing types of concordance factors for networks $N_c^{-}$ of Proposition 9. (L) Gray line segments represent tree-like CFs that arise from quartet networks with no $3_2$-cycle and with no 4-cycle. (C) Gray line segments represent CFs that arise from quartet networks with a $3_2$-cycle. (R) Gray shaded areas represent CFs that arise from quartet networks containing a 4-cycle. In all three figures, the topology of $N_c^{-}$ is marked for the appropriate line segments or regions of CFs