网络流量:真或假

Network Flow : True or False

In a directed graph with at most one edge between each pair of vertices, if we
replace each directed edge by an undirected edge, the maximum flow 
value remains unchanged.

为什么是假的?

为什么流量会发生变化?

谢谢。

因为边缘可能是错误的方式。还有更多有趣的案例,但考虑一下这个微不足道的案例:

S <- T

无论边的容量如何,流量都为零。如果你让它无向,流量将是边的容量。