The other half of the max-flow min-cut theorem refers to a different aspect of a network: the collection of cuts. An s-t cut is a partition of such that and . That is, "s"-"t" cut is a division of the vertices of the network into two parts, with the source in one part and the sink in the other. The cut-set formula_17 of a cut is the set of edges that connect the source part of the cut to the sink part: