an edge of tree is pair of nodes (uvsuch that is the parent of vor vice versa path of is sequence of nodes such that any two consecutive nodes in the sequence form an edge for examplethe tree in figure contains the path (cs /projects/demos/marketexample the inheritance relation between classes in java program forms tree the rootjava lang objectis an ancestor of all other classes each classcis descendent of this root and is the root of subtree of the classes that extend thusthere is path from to the rootjava lang objectin this inheritance tree ordered trees tree is ordered if there is linear ordering defined for the children of each nodethat iswe can identify the children of node as being the firstsecondthirdand so on such an ordering is usually visualized by arranging siblings left to rightaccording to their ordering ordered trees typically indicate the linear order among siblings by listing them in the correct order example the components of structured documentsuch as bookare hierarchically organized as tree whose internal nodes are partsand sectionsand whose external nodes are paragraphstablesfiguresand so on (see figure the root of the tree corresponds to the book itself we couldin factconsider expanding the tree further to show paragraphs consisting of sentencessentences consisting of wordsand words consisting of characters such tree is an example of an ordered treebecause there is well-defined ordering among the children of each node figure an ordered tree associated with book