Events are Not Simple: Identity, Non-Identity, and Quasi-Identity
Eduard H. Hovy, Teruko Mitamura, Felisa Verdejo, Andrew Philpot · 2013
Abstract 1 Despite considerable theoretical and computational work on coreference, deciding when two entities or events are identical is very difficult. In a project to build corpora containing coreference links between events, we have identified three levels of event identity (full, partial, and none). Event coreference annotation on two corpora was performed to validate the findings. 1 The Problem of Identity Last year we had HLT in Montreal, and this year we did it in Atlanta. Does the “did it ” refer to the same conference or a different one? The two conferences are not identical, of course, but they are also not totally unrelated—else the “did it ” would not be interpretable. When creating text, we treat instances of entities and events as if they are fixed, well-described, and well-understood. When we say “that boat over there ” or “Mary’s wedding next month”, we assume the reader creates a mental representation of the referent, and we proceed to refer to it without further thought. However, as has been often noted in theoretical studies of semantics, this assumption is very problematic (Mill, 1872; Frege 1892; Guarino, 1999). Entities and (even more so) events are complex composite phenomena in the world, and they undergo change.