 There is no proper subsituation of Teapots in which 31(b) is true. Since Teapots has nothing but three teapots in it, any proper subsituation of Teapots would have to be one where a part of at least one of the three teapots is missing. But 31(b) is true in Teapots itself, and Teapots is thus a minimal situation in which 31(b) is true.