@startdot digraph associative { rankdir = LR; node [fontsize = 11, shape = circle, style=rounded ]; s1 [label="博多"]; s2 [label="小倉"]; s3 [label="広島"]; s1 -> s2 [label="f"] s2 -> s3 [label="g"] s1 -> s3 [label="g∘f"] } @enddot