Fig. 6From: NANUQ: a method for inferring species networks from gene trees under the coalescent modelFor the tree \(Q_{abcd}\) on the left, \(\rho _{ab}( Q_{abcd})=0\) and \(\rho _{ac} ( Q_{abcd} ) = 1\), since a and c are separated by ab|cd, but a and b are not. For the quartet network \(Q_{abcd}\) on the right, \(\rho _{ab}( Q_{abcd})=1/2\) and \(\rho _{ac}( Q_{abcd})=1\), since the trees displayed by \(Q_{abcd}\) are ab|cd and ad|bcBack to article page