+(** Tryes to find if the system admits solutions.
+ @param lie the list of inequations
+ @return a list that can be empty if the system has solutions. Otherwise it returns a
+ one elements list [\[(c,s,lc)\]]. {b c} is the rational that can be obtained solving the system,
+ {b s} is true if the inequation that proves that the system is absurd is of type [c < 0], false if
+ [c <= 0], {b lc} is a list of rational that represents the liear combination to obtain the
+ absurd inequation *)