A fractional clique of a graph is a nonnegative real function on the vertices of such that sum of the values on the vertices of any independent
set is at most one.
The weight of a fractional clique is the sum of its values, and the maximum possible weight of a fractional clique is called the fractional
clique number.
is a nonnegative real function on the vertices of 
such that sum of the values on the vertices of any independent
set is at most one.
