Definition 1: A path is a Continuous, Unidirectional Succession of branches along which no node is passed more than once. For example, x, to x, to X, to X4 X2,Y, and back to x, and x, to x, to x4 are paths Definition 2 An Input Node Or Source is a node with only outgoing branches. For example, x is an input node Definition 3: An Output Node or sink is a node with only ADefinition 1: A path is a Continuous, Unidirectional Succession of branches along which no node is passed more than once. For example, to to to , and back to and to to are paths. X1 X 2 X 3 X 4 2 3 X , X X 2 X1 X 2 X 4 Definition 2: An Input Node Or Source is a node with only outgoing branches. For example, X1 is an input node. Definition 3: An Output Node Or Sink is a node with only incoming branches. For example, is an output node. X 4