In our annotation practice, we often find that some groups of FEs seem to act like sets, in that the presence of any member of the set is sufficient to satisfy a semantic valence of the predicator. We refer to such a group of FEs as a coreness set, or CoreSet. For instance, Source, Path, and Goal are core FEs in the various motion frames in the database. However, although possible, it is not necessary, and in fact unusual, for all three FEs to co-occur, as in example (14). Sentences in many motion frames can be informationally complete and pragmatically felicitous with just one or two of the FEs expressed, as shown in (15)-(18). (14) Fred went [from Berkeley Source] [across North America and the Atlantic Ocean Path] [to Paris Goal]. (15) Martha hiked [from Berkeley Source] [to Oakland Goal]. (16) Elaine walked [to Monterey Goal]. (17) I saw Peter sneak [past the guard Path]. (18) Juan was walking [out of the office Source] when I arrived. FrameNet's normal annotation practice demands that we account for all core FEs and we could keep track of the un-instantiated FEs in the example sentences above by using null-instantiation labels as described in section (3.2.3). However, we prefer to group the FEs in CoreSets and not mark null instantiation for each member FE in cases where the FEs have an informational and conceptual interdependence. Source, Path, and Goal, for instance, are clearly related via a notion that we might call 'full path'. By contrast, omission of the Ingestibles for eat in the Ingestion frame is not related to the presence or absence of any other frame element. The sentence I'm eating __ (with my friends/in the kitchen/now) is acceptable with or without any of the frame elements given in parentheses expressed. xsd:string