A note on definitions of trees

A number of definitions of trees appear in various courses of a computer engineering curriculum such as circuits or data structures. It is shown that a commonly used recursive definition of a tree is equivalent to a graph-theoretic definition. This puts the recursive definition in a better perspective relative to the various equivalent forms of graph-based trees. Pedagogically, as both types of definitions are often introduced to students even in the same course, this approach should provide a strong basis for students to understand their relationship.