REQUIREMENTS _ _ _ _ _ _ _ _ _ _ _ _ variable

After an attempt to solve an inconsistent equation system with parameters, the variable requirements contains a list of expressions. These expressions define a set of conditions implicitly equated with zero. Any solution to this system defines a setting for the parameters sufficient to make the original system consistent.

examples:

solve({x-a,x-y,y-1},{x,y}); 

  {}


requirements;

  {a - 1}