RE: positive dihedral/negative
Dihedral is defined as an upward angle from horizontal from root to tip, as viewed from fore or aft. That is to say when viewed normally, right side up and all that, the wing tips are higher than the wing root. Anhedral is the opposite; negative dihedral if you wish to put it those terms. Not bent per se, but two wing halves joined together, the joint being other than 180 degrees.