Augmenting path

The Graph <math> G_f = (V,E_f) </math> is defined as the residual graph relative to f, where <math> E_f </math> is the set of residual edges. A path <math> P \in G_f </math> from the source <math> s</math> to the sink <math> t</math> is called augmented path[?] of <math> f</math>. This path can be used to increase the flow from <math> s</math> to <math> t</math>.