For example, the precedence graph for schedule 1 in Figure 14.10a contains
the single edge T1 → T2, since all the instructions of T1 are executed before the
first instruction of T2 is executed. Similarly, Figure 14.10b shows the precedence
graph for schedule 2 with the single edge T2 →T1, since all the instructions of T2
are executed before the first instruction of T1 is executed.