Function prop::quality::naq_left

pub fn naq_left<A: Prop, B: Prop, C: Prop>(
    q_ab: Aq<A, B>,
    sesh_ac: Not<Aq<A, C>>
) -> Not<Aq<B, C>>

(a ~¬~ b) ⋀ ¬(a ~¬~ c) => ¬(b ~¬~ c).