Network Flow A fow in Gis a real-valued function fon vertex pairs having the following four conditions: (1)Skew symmetry.vu,velu,=-v).We say there is a flow from uto vif,>0. (2)Capacity constraints.Vu,veV,u,vsdu,v. We say edge (u,v)is saturated if u,=du,v). (3)Flow conservation.Vue s,veu,v)=0.In other words,the net fow(total flow out minus total flow in)at any interior vertex is 0. (4)廿vEVy)=0.Network Flow A flow in G is a real-valued function f on vertex pairs having the following four conditions: (1) Skew symmetry. u, vV, f(u, v)=-f(v, u). We say there is a flow from u to v if f(u, v)>0. (2) Capacity constraints. u, vV, f(u, v)c(u, v). We say edge (u, v) is saturated if f(u, v)=c(u, v). (3) Flow conservation. uV-{s, t}, vV f(u, v)=0. In other words, the net flow (total flow out minus total flow in) at any interior vertex is 0. (4) vV, f(v, v)=0