Incoming ...

[TODO]

Tree and Graph traversal algorithms.
* Preorder
* Inorder
* Postorder
These algorithms are used for searches and operations.

Trees could be used in undirected graphs for traversals.

Figure. Minimal spanning tree obtained from a large group of stocks traded on the New York Stock Exchange during a 12-year trading period [Mathaware].

* For every graph you can define spanning tree. Spanning tree T is a connected graph G if T is sub graph of G and T contains all vertices of G. In other words spanning trees are graph without cycles. Spanning trees are highly important to explain routing, information dissemination info in social networks, etc. Nevertheless, spanning tree of graph is not unique. You can make several spanning tree of a graph though minimal spanning trees of graphs are unique. Prim and Kruskal algorithms could be used to obtain minimal spanning tree of a graph.
* Cut-set: In a connected graph G, a cut-set is a set of edges whose removal from G leaves G disconnected, provided removal of a proper subset of these edges disconnects G.

Figure: New York region road segments between the forty-five- and fifteen-mile radii circles showing the eighty-nine minimum cut-set segments, and a twenty-five-mile intermediate radius circle [HomelandSecurity].


Taking points:
* Tree with n nodes has (n-1) edges.