theorem
  max(f,Umf(C1,C2)) = Umf(C1,C2) & min(f,Umf(C1,C2)) = f & max(f,Zmf(C1,
  C2)) = f & min(f,Zmf(C1,C2)) = Zmf(C1,C2)
proof
A1: Umf(C1,C2) = UMF [:C1,C2:];
  Zmf(C1,C2) = EMF [:C1,C2:];
  hence thesis by A1,FUZZY_1:18;
end;
