Counting Planar Tanglegrams
Dimbinaina Ralaivaosaona, Jean Bernoulli Ravelomanana, Stephan G. Wagner · DROPS (Schloss Dagstuhl – Leibniz Center for Informatics) · 2018
Tanglegrams are structures consisting of two binary rooted trees with the same number of leaves and a perfect matching between the leaves of the two trees. We say that a tanglegram is planar if it can be drawn in the plane without crossings. Using a blend of combinatorial and analytic techniques, we determine an asymptotic formula for the number of planar tanglegrams with n leaves on each side.