Definition

nonempty Vertices, Edges set의 집합

Representation

양방향 (undirected graph)

V(G1) = {0, 1, 2, 3} ; E(G1) = {(0, 1), (0, 2), (0, 3), (1, 2), (1, 3), (2, 3)}

단방향 (directed graph)

V(G3) = {0, 1, 2}; E(G3) = {<0, 1>, <1, 0>, <1, 2>}

Restriction

self edges를 허용하지 않음 ↔ graph with self loops

multiple occurrences of the same edge를 허용하지 않음 ↔ multigraph

Complete graph

n개의 vertices와 n(n−1)/2 edges를 가진 그래프

fully connected graph라고 쓰지말고 complete graph 기억하자

adjacent, incident

verticies u, v : adjacent

edge (u, v) : incident

directed graph에선 좀 다름

Subgraphs

Walk vs Path