Consider a “pseudo-ordering” on the complex field defined by saying a complex number is positive if and only if
is positive. Which of the three order axioms (listed in the previous exercise) are satisfied.
The second and third axioms are satisfied, but not the first.
The second axiom states that for every with
either
is positive or
is positive, but not both. By our definition,
positive implies
. Therefore, since
we have
. Hence,
is not positive.
The third axiom is satisfied since by our definition of positive if and
, then
is not positive.
Finally, the first axiom fails since if we take , then
is positive, but
is not positive.
The second axiom is NOT satisfied ,consider i, it’s not zero yet both i and -i are not “positive” since their real part is not positive.