Endknoten

Endknoten is a term used in graph theory and network design to denote a node at the end of a connection. In a simple undirected graph, an Endknoten is typically a vertex with degree 1, i.e., a leaf. Such vertices lie on the boundary of the graph and are not part of any cycle, unless the graph consists of a single edge.

In directed graphs, the meaning depends on context. It can refer to a vertex with no outgoing edges (a sink) or more generally to a terminal point of a path. Some applications distinguish between sources (nodes that can only originate paths) and Endknoten. In trees, leaves are treated as Endknoten.

In practical applications, Endknoten often represent end users or endpoints of a network link, such as computers, phones, sensors, or devices at the edge of a network. They are usually not transit points for traffic; their role is to receive or originate connections. Algorithms that operate on graphs, such as traversal, shortest-path, or connectivity analyses, may treat Endknoten differently from internal nodes to reflect their boundary role or to optimize performance.

The concept also appears in other domains, where terminal points are defined as endpoints of chains, circuits, or sequences. While not all fields use the exact term Endknoten, the underlying idea of an endpoint or leaf node is common across disciplines.