  The notion of forcing sets for perfect matchings was introduced by Harary,
Klein, and \v{Z}ivkovi\'{c}. The application of this problem in chemistry, as
well as its interesting theoretical aspects, made this subject very active. In
this work, we introduce the notion of the forcing function of fractional
perfect matchings which is continuous analogous to forcing sets defined over
the perfect matching polytope of graphs. We show that our defined object is a
continuous and concave function extension of the integral forcing set. Then, we
use our results about this extension to conclude new bounds and results about
the integral case of forcing sets for the family of edge and vertex-transitive
graphs and in particular, hypercube graphs.
