theorem
  f \+\ UMF(C) = 1_minus f
proof
  thus f \+\ UMF(C) = max(min(f,EMF(C)),min(1_minus(f),UMF(C))) by Th39
    .= max(EMF(C),min(1_minus(f),UMF(C))) by Th17
    .= min(1_minus(f),UMF(C)) by Th17
    .= 1_minus f by Th17;
end;
