reserve c for Complex;
reserve r for Real;
reserve m,n for Nat;
reserve f for complex-valued Function;
reserve f,g for differentiable Function of REAL,REAL;
reserve L for non empty ZeroStr;
reserve x for Element of L;
reserve p,q for Polynomial of F_Real;

theorem Th54:
  p is constant implies Eval(p)`| = REAL --> 0
  proof
    assume p is constant;
    then p = 0_.F or p = <%p.0%> by Th23;
    hence thesis by Th52,Lm2,Th11;
  end;
