 A Böhm-like tree is a (possibly infinite) directed acyclic graph having some vertices labelled with lambda terms of the form λ"x"1.λ"x"2...λ"x"n."y" ("n" may be 0), where exactly one vertex (the "root") has no parent, all other vertices have exactly one parent, every vertex has a finite number of children, and every unlabeled vertex has no children.Let us have the following notions for Böhm-like trees "A", "B"