Nodes or vertices): set V = { A, B, C, D, E, F }LINKS (edges): set E = { (A,B), (A,C), (A,D), (C,E), C,F) }GRAPH: collection of vertices and edges: G(V,E)A Tree structure is a “connected” graph with no “cycles,” i.e., every node has at least one link to another nodeand only one path exists between any two nodes.Via a link, a node can be a parent or a child of another node.A node without a child is called a terminal or leaf node(e.g., the nodes at the bottom of the tree: B, D, E, and F)A node with children is a non-terminal or internal node(e.g., A and C);The root node is a special internal node with no parent (e.g., A).Organization Charts are Trees (w/ boxesinstead of circles)( Often the name of the tree is inherited from the name of the root node - e.g., A ):AAABCDBCDFigure 1: Tree Graph Definitions and TermsTerms like “unit” or “structure” are ambiguous in isolation; therefore, a more formal definition is required. Using the tree graph formalism, a node of a tree can be named an “organization” (e.g., node A in Figure 1 is called Organization A.). The term “association” can be used to refer to a link of a tree (e.g., the lineconnecting nodes A and C, denoted by (A,C), in Figure 1 can be called association “AC”, or more specifically, organization-association “AC”). An organization chart is a tree graph composed of a set of nodes and a set of links, or in this new vernacular, a set of organizations and a set of organization-associations. For convenience, the graph can be called a “unit.” Thus, a unit (a graph) is composed of organizations and organization-associations. The action of moving from node to node along the links of a graph is called “traversing” the graph and there are numerous, well-knownalgorithms for doing this. The links and nodes of a graph may includeadditionalattributes to allow them to be filtered (i.e., selected or deselected) during the traversal process. This allows differentpaths to be followed by applying parameterconstraints during the traversal process, as is illustrated in Figure 2. The left-most graph, marked “Base,” shows all the nodes and links with the addition of a label a, b, or c. To traverse this tree, one provides a set of permissiblelabels to be used during the traversal process. The middle graph illustrates the case in which only nodes and links with a label of a or c are included. The right tree illustrates the case in which only nodes and links with a label of b or c are included. One can include as many different l...