You know that for a potential function (conservative force/fields) that

$\nabla U = \pm \vec{F}$

In math, we don't have that minus sign, we have only the plus one. 

What does it mean if you get rid of the plus sign? I remember the minus signs tells us that the force is always in the opposite direction of the increasing potential function. Does math tell me there exists a potential function such that it's force also increases as potential goes up?