Fig. 7From: Predicting horizontal gene transfers with perfect transfer networksAn illustration of \(f(x) = z\) for a marked node \(p_x\) that has a closest marked descendant \(p_y\). Here, the characters of x must be a subset of the characters of y, as otherwise x would be a first appearance. We can then argue that a character of \(y \setminus x\) has its first appearance between \(p_x\) and \(p_y\)Back to article page