Fig. 1

From the left side: a gene tree G and a species tree S with the lca-mapping M shown using arrows from the internal nodes of G to the nodes of S. There are 5 gene duplications, 2 speciation nodes in G (red bars), and 8 valid mappings depicted as embeddings of G into S [4], where the blue lines in these embeddings correspond to the edges of G. \(E_{LCA}\) is induced by the lca-mapping. Here, EC (G, S) as depicted in the three rightmost scenarios with episode sets \(\{a, b, abcd\}\) for \(E_5\) and \(\{a, abc, abcd\}\) for \(E_6\) and \(E_7\). The example trees are partially adapted from [24]