Take a bitcoin public key (x, y) and its additive inverse (x, -y). How do you identify which is the positive point and which is the negative point?
The sign (or more precisely even/odd) is determined simply by the value of the least-significant bit Notice that the values of the LSBs for Y and -Y are opposites in all of your examples. That's why they are referred to as even/odd and not positive/negative.
To answer your question, there is no "positive/negative". All numbers are positive.