theorem
  f\(g\h) = max(f\g,min(f,h))
proof
  f\(g\h) = min(f,max(1_minus g,1_minus(1_minus h))) by FUZZY_1:11
    .= max(min(f,1_minus g),min(f,h)) by FUZZY_1:9;
  hence thesis;
end;
