# Tree with alternating types of nodes

Suppose that I have a tree where each node is either of type A or type B.

Nodes of type A have outgoing edges only to nodes of type B and vice versa.

Is there a name/term for this kind of a tree?

A concrete example of such a tree would be the state tree of a 2 player game (like tic-tac-toe) which has alternating levels of states where it's X's turn or Y's turn.

• In computing model, there is an ATM (Alternative Turing machine) which has some similarity to the above definition of the tree. In this model, every node has either existential type or universal. The machine has no transition rule between nodes with the same type. – Doralisa Dec 16 '18 at 16:44