
theorem Th37:
for X be non empty set, F be Functional_Sequence of X,ExtREAL, n be Nat
 holds (-F).n = -(F.n)
proof
  let X be non empty set, F be Functional_Sequence of X,ExtREAL, n be Nat;
  thus (-F).n = (-1)(#)(F.n) by Def1 .= -(F.n) by MESFUNC2:9;
end;
