 Second, there is the relativizing strategy. As noted above, some philosophers hold that the fundamental parthood relation is three-place or four-place, with the additional argument places reserved for locations of the part and/or the whole. For example, to allow for multilocation and mereological variation from one location to another, Gilmore (2014b: 21) suggests taking the predicate ‘x at y is a part of z at w’ as primitive and using it to define ‘x is exactly located at y’, as ‘for some z and some w: either x at y is a part of z at w or z at w is a part of x at y’. The definition of the existence-at relation in Thomson (1983) is an early example of this strategy. To keep things simple, however, we will continue to assume that the fundamental parthood relation is two-place. So we will set the relativizing strategy aside.