
theorem Th34:
for X be non empty set, f be PartFunc of X,ExtREAL holds
 max+f = max-(-f)
proof
    let X be non empty set, f be PartFunc of X,ExtREAL;
    -f = (-1)(#)f by MESFUNC2:9; then
    max-(-f) = (- -1)(#)max+f by Th33;
    hence thesis by MESFUNC2:1;
end;
