Fig. 1
From: Predicting horizontal gene transfers with perfect transfer networks
1 A species tree T with a set of taxa \(\mathcal {S}\) on characters \(\mathcal {C}= \{a,b,c\}\). 2 A PTN with T as base tree that explains \(\mathcal {S}\). Red arrows represent transfer edges. 3 Another PTN with T as base tree that also explains \(\mathcal {S}\). Note that this PTN requires two less transfers. 4 A tree-based network G with \(\mathcal {S}-\)map \(\sigma\) for which no labeling can explain \(\mathcal {S}\)