Salmon-Alt & Romary on Reference Annotation Fourth workshop on multimodal semantic representation, Tilburg Jan 2005

J.L.Borges quoting a (spurious) Chinese encyclopaedia Animals are divided into (slightly abbreviated) those that belong to the emperor embalmed ones those that are trained stray dogs those that tremble as if they were mad those drawn with a very fine camelhair brush those that have just broken a flower vase those that from a long way off look like flies

How I understand Alt & Romary Goal: establish set of attibutes + values for reference-related annotations that can help NLP Without such a goal, any classification would do: –classify NPs according to the number of characters –classify animals according to number of their legs But surely, these distinctions would be irrelevant to NLP …

… or is it? –“The man was chasing Fido. His hind legs were hurting” [man has no hind legs] –Johnny: `shit’. Mom: `That’s a four-letter word!’ [number of characters does count] Perhaps ultimately, reference annotation is AI- complete Proposal is about which properties of markables matter systematically for NLP Similar for links (= relations) between an NP and the surrounding text

We discuss 1.Markables 2.Links between markables

I. Markables What is a markable? –Not necessarily a referring NP E.g., `un village … son eglise’ –Does a markable even have to be an NP? No: an NP can refer back to something that’s not an NP: - `John hit Bill. He’ll regret having done this’ - `Do not swallow. This is important / dangerous’ –MUC: annotators find it difficult to decide what’s a markable, e.g. in compound nouns (e.g., `corrugated steel plating’)

Markables (ctd.) I’ll focus on one set of concepts, called “Referential Descriptors” (section 3.1.2) NB: These are properties of the referent! Cardinality (0,1,2,3,…?) Natural gender (male, female, …) Definiteness (identifiable, indefinite/generic term/nonspecific term) Information status (old, mediated, new)

Markables (ctd.) Cardinality (0,1,2,3,…) “specifies exact quantity” How about `Some people were sneezing’, `Most people were sneezing’, `The people were sneezing Natural gender (male, female, …) Definiteness (identifiable, indefinite/generic term/nonspecific term) Is this a property of the referent? Information status (old, mediated, new) Is this a property of the referent?

Markables (ctd.) Why not … Animacy (treated as lexical, but `the dog’ is inanimate when referring to a sculpture) Count/mass (treated as lexical, but `the wine’ can refer to object or mass) Collective/distributive (treated as lexical, but consider `three men lifted a piano’ ) Abstract/concrete. Consider `The Decline and Fall of the Roman Empire’ Human/nonhuman (`Fido bit Ben. He said..’) Q scope (`Every man loves a woman; she …’)

These are just examples The issue is: do we have a principled way of deciding which concepts belong in a categorisation of this kind? Presumably, `usefulness for NLP’ should somehow play a role

II. Links Van Deemter & Kibble 2000: Existing annotation schemes confuse coreference, anaphora, and a function taking a value –`The temperature is 90 degrees; it is going up’  90 is going up (MUC) Alt & Romary: distinguish between Object Relations and Linguistic Relations

II. Links (ctd.) Distinction looks sensible. But consider: –`Tony Blair is the PM’ Linguistic relation: predication Object relation: identity –`Tony Blair was the PM’ Linguistic relation: predication? Object relation: past identity?? –`Gordon Brown may be the (next) PM’ Linguistic relation: predication?? Object relation: possible (future) identity???

Under modality/tense/attitudes, simple concepts like identity start bifurcating. Should this be reflected in reference annotation schemes? (And if so, how?)

II. Links (ctd.) –`The PM is not highly regarded in his party these days: Tony is George’s pony.’ Linguistic relationship: none (?) Object relationship: identity (How wrong would it be to say that the linguistic relation is anaphora?) Is a Linguistic Relation one that can be observed at string level?

Summing up 1. Is the notion of a markable clear enough to make sense to an annotator? Is the notion of a referring NP relevant here, and do we know what that is? E.g., in attitude contexts, it is not clear: `Jaime claims that the monster of Loch Ness is restless, and that it …’

Concluding questions (ctd.) 2. How about anaphora to VPs or sentences? - `John hit Bill. He’ll regret having done this!’ - `Do not swallow. This is important / dangerous’ 3. How about reference to text? E.g., `the concluding section of this paper’, or simply `this word’. (See PhD thesis I.Paraboni) 4. Is the notion of a `referential descriptor’ coherent? Do we have a principled way of deciding which referential descriptors are legitimate? (Similar for other descriptors)

Concluding questions (ctd.) 5. Links: Identity is a key `object relation’. But how about past identity, possible identity, etc? Compare earlier remark about reference: everyday concepts become muddy in modal contexts!

Concluding questions (ctd.) 6. I take it that this is not an annotation scheme (cf., MUC, MATE), but a set of concepts that such a scheme could use (cf., Bunt & Romary 2004) What adaptations can a particular scheme make? E.g., are additions allowed?

Time to let others have their say!