I have a network flow (with min and max capacities) where the only transport units flowing are within a cycle (of flow value 2). The source of the network does not send out any transport units into any direction and the transport units getting into the sink are all getting sent away directly, so 0 transport units "stay" there. Now my question is, is such a flow allowed as long as minimium neccesarry flow (given by min capacities) exists and the amount of incoming transport units is equal to the amount of outgoing transport units? Or is a flow network where the source doesn´t send out any transport units not permitted?
I look forward for any help.