A **flow**
is a real-valued function
representing the rate of flow between u and v, constrained by the
following:

- 1.
- Capacity Constraint f(u,v)
c(u,v)
- 2.
- Skew Symmetry f(u,v) = -f(v,u)
- 3.
- Flow Conservation For every u
V - {s,t},
.

The total flow into and out of a vertex u is 0.

The value of f(u,v) is the **net flow** from vertex u to vertex v.

Note that if (u,v) and (v,u) E, then f(u,v) = f(v,u) = 0.

The **value** of a flow f is
.