 reserve A for non empty Subset of REAL;

theorem
  for a,b,c be Real, f be Function of REAL,REAL st
    b > 1 & c > 0 &
  ( for x be Real holds f.x = min(1, max(0, b - |. b*(x-a)/c .|)) )
    holds
  f is trapezoidal FuzzySet of REAL &
  f is normalized FuzzySet of REAL by Lm1,Lm2;
