On the Algebraic Atructure of Rooted Trees

Figure 1.1 Figure 1.2 These two digraphs, while different, usually represent the same phenomenon, say, the same “computational process.” Our interest in rooted trees stems from the fact that these two digraphs “unfold” into the SAME infinite tree. In some cases at least it is also true that different (i.e. non-isomorphic) trees represent different phenomena (of the same kind). In these cases the unfoldings (i.e. the trees) are surrogates for the phenomena.