Prove that for every natural number n, the set { m/n :m is a natural numer} is unbounded above in R.
Prove:,
is unbounded above in
.
Proof: Fix. Assume
is bounded; i.e.
such that
. This implies that
. Because
is a constant, though, the previous statement implies that
is bounded above by
, which is of course a ridiculous statement. Thus we have a contradiction and
is unbounded above.