Paola,
By a
strict definition, tree (diagram) is a plane figure that branches from a single
root, what makes a graphic way to represent any hierarchical structure. Created
as the mixed metaphors after family relationships (parent/child), graph theory
(node), and botanic notions, the tree vocabulary is marked by the root
nodes (superior, ancestor), internal nodes (parent/child), leaf nodes (child);
subtrees and forest, a set of rooted trees.
In a
sense, trees are everywhere, whenever you deal with a hierarchical
order:
1. in
order theory and set theory, the tree structure makes a special kind of
partial order;
2. in
graph theory, it makes a connected acyclic graph, undirected or
directed;
3. in
knowledge representation, it reflects all taxonomic knowledge;
4. in
family, it represents phylogenetic family trees, cladograms;
5. in
society, any hierarchical social structure;
6. in
linguistics, syntactic phrasal structure as S > NP VP;
7. in
library science, Dewey Decimal System;
8. in
internet and Telecommunications, root nodes servers, domain servers,
etc;
9. in web,
Yahoo subject index, OPD, the arrangement of web pages in a web site
10. in
computing, tree data structure.
regards,
azamat
abdoullaev