Our Father, who art in heaven, hallowed be thy name; thy kingdom come; thy will be done on earth as it is in heaven. Give us this day our daily bread; and forgive us our trespasses as we forgive those who trespass against us; and lead us not into temptation, but deliver us from evil.

A sufficient condition for the Verma module V to have a singular vector at the level N is h = h_{r,s}(c) for some positive integers r, s such that N = r. In particular, h_{1,1}(c) = 0 and the reducible Verma module V has a singular vector L_{-1}v at the level N = 1.