 There are, however, fifteen other ways of expressing (P.4) in terms of π, obtained by re-writing one or both occurrences of ‘= 1’ as ‘&gt; 0’ and one or both occurrences of ‘= 0’ as ‘&lt; 1’. In the presence of bivalence, these would all be equivalent ways of saying the same thing. However, such alternative formulations would not coincide if π is allowed to take non-integral values, and the question of which version(s) best reflect the supplementation intuition would have to be carefully examined. (See e.g. the discussion in N. Smith 2005: 397.) And this is just the beginning: it is clear that similar issues arise with most other principles discussed in the previous sections, such as Complementation, Density, or the various composition principles. (See e.g. Polkowsky and Skowron 1994: 86 for a formulation of the Unrestricted Sum axiom (P.152).)