[tag=PRP] □ □ □
[tag=PRP] □ □ □ □
[tag=PRP] [] □ □
Graduate students may audit a course when they wish to receive instruction in a particular area but do not wish to receive a grade or credit . Drug seeking is not in itself evidence of craving if we wish to postulate craving as an independent entity . If you wish to join PCP-discuss , please send in the subscription form . If you wish to take time out you should seek advice from your department before doing so . We wish to compare M with M ' in order to derive a corresponding bound on the mixing time of M.