Title: Information Structure Resolution as an Anaphora Problem
1Information Structure Resolution as an Anaphora
Problem
2What Info Structure has to do with anaphora
- There is a general agreement the focus-background
partitioning depends on the context, i.e. is
anaphoric (in a general and intuitive sense!).
3What Info Structure has to do with anaphora
- There is a general agreement the focus-background
partitioning depends on the context, i.e. is
anaphoric (in a general and intuitive sense!).
E.g (1) a. What about Paul? b. The company
FIRED bkPaul.
4What Info Structure has to do with anaphora
- There is a general agreement the focus-background
partitioning depends on the context, i.e. is
anaphoric. - The reading aloud challenge (recoverability)
5What Info Structure has to do with anaphora
- There is a general agreement the focus-background
partitioning depends on the context, i.e. is
anaphoric. - The reading aloud challenge (recoverability)
- There are, however, important differences between
background elements and other anaphora.
6What Info Structure has to do with anaphora
Pronouns and donkey sentences in DRT (2) a)
Every linguist discusses a donkey sentence b)
It is a rather complex sentence.
- There is a general agreement the focus-background
partitioning depends on the context, i.e. is
anaphoric. - The reading aloud challenge (recoverability)
- There are, however, important differences between
background elements and other anaphora.
z,
z?.
x
y
linguist (x)
donkey_s (y)discuss(x,y)
7What Info Structure has to do with anaphora
Why does that not extend to backgrounded
material? (3) a) Every linguist discusses a
donkey sentence b) ok Donkey sentences are
beautiful b) ok Linguists LIKE bgdonkey
sentences
- There is a general agreement the focus-background
partitioning depends on the context, i.e. is
anaphoric. - The reading aloud challenge (recoverability)
- There are, however, important differences between
background elements and other anaphora.
z, ...
Why can the backgrounded donkey sentences be
anaphoric outside the sub-DRS???
donkey_s(z) anaphoric(z,y)
x
y
linguist (x)
donkey_s (y)discuss(x,y)
8What Info Structure has to do with anaphora
Why does that not extend to backgrounded
material? (3) a) Every linguist discusses a
donkey sentence b) ok Donkey sentences are
beautiful b) ok Linguists LIKE bgdonkey
sentences
- There is a general agreement the focus-background
partitioning depends on the context, i.e. is
anaphoric. - The reading aloud challenge (recoverability)
- There are, however, important differences between
background elements and other anaphora.
The accessibility problem
z, ...
Why can the backgrounded donkey sentences be
anaphoric outside the sub-DRS???
donkey_s(z) anaphoric(z,y)
x
y
linguist (x)
donkey_s (y)discuss(x,y)
9What Info Structure has to do with anaphora
Other examples/problemsGeneric (kind refering)
NPs(4) a. Pirates are scum b. Nevertheless
Mary MARRIED bga pirate.Bridging (5) a. The
motor broke. b. So, John bought a NEW car.
antecedent underspefication (cf. Van Deemter
1993)(6) a) Mozart wrote a lotta pieces for the
viola. b) He must have LOVED bgstring
instruments
- There is a general agreement the focus-background
partitioning depends on the context, i.e. is
anaphoric. - The reading aloud challenge (recoverability)
- There are, however, important differences between
background elements and other anaphora.
10What Info Structure has to do with anaphora
Other examples/problemsGeneric (kind refering)
NPs(4) a. Pirates are scum b. Nevertheless
Mary MARRIED bga pirate.Bridging (5) a. The
motor broke. b. So, John bought a NEW car.
antecedent underspefication (cf. Van Deemter
1993)(6) a) Mozart wrote a lotta pieces for the
viola. b) He must have LOVED bgstring
instruments
- There is a general agreement the focus-background
partitioning depends on the context, i.e. is
anaphoric. - The reading aloud challenge (recoverability)
- There are, however, important differences between
background elements and other anaphora.
The non-identity problem
11What Info Structure has to do with anaphora
- Hypothesis
- Backgrounded material can be treated as anaphora
if - The context model is rich enough (bridging,
underspecification, ) - We have a way to explain why some anaphora do not
respect accessibility constraints (cf donkey
sentences)
12What Info Structure has to do with anaphora
ANOTHER QUESTION If IS resolution turns out
to be a purely anaphoric process, why does NL
bother to code it syntactically, phonologically,
morphologically, typographically .
13What Info Structure has to do with anaphora
ANOTHER QUESTION If IS resolution turns out
to be a purely anaphoric process, why does NL
bother to code it syntactically, phonologically,
morphologically, typographically .
The theoretical status problem
14Two sources to inherit from
- Event Semantics and Bachs (1986) algebraic
treatment of event (and other referents) - Van der Sandts (1992) theory of presupposition /
presupposition accommodation as Anaphora
Resolution
15Event Semantics Bach (1986)
- Different (sorted) domains of reference
- - individuals (incl. plural individuals)
- - stuff which the individuals are made of
(properties/kinds) - - atomic events
- - bounded processes (bits of processes)
16Event Semantics Bach (1986)
- Each of these domains has the structure of a
complete semi-joint lattices
17Event Semantics Bach (1986)
- Each of these domains has the structure of a
complete semi-joint lattices
En example for Individuals (singular and plural)
John Paul Ringo
John Paul
John Ringo
Paul Ringo
Paul
John
Ringo
18Event Semantics Bach (1986)
- Additional components
- Temporal relations overlap and precedence
- A homomorphism which maps individuals to the
stuff they are made of and atomic events to
bounded events (the bits of process
19Event Semantics Bach (1986)
- Some modifications we will make to this proposal
(in part taken from Carlson 2001) - 1) There are 4 domains
- entities (individuals)classes of entities
(kinds, properties) - events
- classes of events
20Event Semantics Bach (1986)
- Some modifications we will make to this proposal
(in part taken from Carlson 2001) - 2) The semi-joint lattice structure of each
domain can be (partially) represented by a simple
part-of relation - run move
- eat cake eat
- cat mammal animal
21Event Semantics Bach (1986)
- This bit of theory should help to (partially)
solve the non-identity problem - (6) a) Mozart wrote a lotta pieces for the
viola. b) He must have LOVED bgstring
instruments - viola string instruments
- ? string instruments is a legal antecedent for
viola -
22Event Semantics Bach (1986)
- (9) Mantenir viva una planta no és fà cil. Jo
tenia un amic que els bitxos sels hi menjaven
totes. Quan no era el pulgó, eren les erugues.
Quan matava les erugues, li sortia la cochinilla,
un nom lleig, també... Un nom dinsecte guarro. I
la mosca blanca. - Al principi estava preocupat, el tio, però al
final els hi va acabar agafant carinyoi tot,
bgals bitxos. (57) -
- Buenafuente, cited in Mayol (2002)
23Van der Sandt (1992)
- Presupposition resolution is the same mechanism
as anaphora resolution. - (7) John has a wife. Johns wife is a singer.
- The possesive introduces an existential
presupposition.
24Van der Sandt (1992)
- If the (existential) presupposition does not meet
an antecedent, the existence of the presupposedly
existing referent will be introduced by
accommodation.
25Van der Sandt (1992)
(7) a) John has a wife.
- If the (existential) presupposition does not meet
an antecedent, the existence of the presupposedly
existing referent will be introduced by
accommodation.
x, y
john(x)wife(y)has(y,x)
26Van der Sandt (1992)
(7) a) John has a wife. b) Johns wife is a
singer
- If the (existential) presupposition does not meet
an antecedent, the existence of the presupposedly
existing referent will be introduced by
accommodation.
x, y, z
john(x) wife(z)wife(y) zyhas(y,x) of(y,x)
singer(z)
27Van der Sandt (1992)
(8) Johns wife is a singer
- If the (existential) presupposition does not meet
an antecedent, the existence of the presupposedly
existing referent will be introduced by
accommodation.
x, y
john(x)wife(y)of(y,x)singer(y)
y is introduced via presupposition accomodation
28Van der Sandt (1992)
- Presupposition accommodation can introduce a
referent in a higher DRS than the one in which
the presupposition is triggered - (10) a) Every critic liked Jacksons film.
- b) It is a nice piece of work.
29Van der Sandt (1992)
(10) a) Every critic liked Jacksons
film.
- Presupposition accommodation can introduce a
referent in a higher DRS than the one in which
the presupposition is triggered - (10) a) Every critic liked Jacksons film.
- b) It is a nice piece of work.
y
Jackson (y)
x
z
critic (x)
film (z)of (z,y)like (x,z)
30Van der Sandt (1992)
(10) a) Every critic liked Jacksons
film.
- Presupposition accommodation can introduce a
referent in a higher DRS than the one in which
the presupposition is triggered - (10) a) Every critic liked Jacksons film.
- b) It is a nice piece of work.
y
Jackson (y)
Presuppositions can be introduced in a higher DRS!
x
z
critic (x)
film (z)of (z,y)like (x,z)
31Van der Sandt (1992)
(10) a) Every critic liked Jacksons
film.
- Presupposition accommodation can introduce a
referent in a higher DRS than the one in which
the presupposition is triggered - (10) a) Every critic liked Jacksons film.
- b) It is a nice piece of work.
y, z
Jackson (y)
x
critic (x)
film (z)of (z,y)like (x,z)
32Van der Sandt (1992)
(10) a) Every critic liked Jacksons film. b) It
is a nice piece of work.
- Presupposition accommodation can introduce a
referent in a higher DRS than the one in which
the presupposition is triggered - (10) a) Every critic liked Jacksons film.
- b) It is a nice piece of work.
y, z, v
Jackson (y) vznice_piece_o_work(z)
x
critic (x)
film (z)of (z,y)like (x,z)
33Class is a question of presupposition
- Hypothesis 1 The existence of an discourse
referent presupposes the existence of the class
it belongs to.
34Class is a question of presupposition
- Hypothesis 1 The existence of an discourse
referent presupposes the existence of the class
it belongs to.
Example The indefinite NP a cat (11) A cat
Introduces an discourse referent x, such that
cat (x). But it also presupposes that there is a
class of entities which share the property of
being cats.
35Class is a question of presupposition
- Hypothesis 2There are different types of
discourse referents entities, events and their
respective classes
36NOW
37Extending DRT Typed variables
x, y, e
gat(x)peix(y)menjar(e)agent(e,x)patient(e,y)t
ime(e, now)aspect(e, .....)
38Extending DRT Typed variables
Now we associate each referent to domain it
belongs to. Note that we have already introduced
e as a referent for the event eat.
x, y, e
gat(x)peix(y)menjar(e)agent(e,x)patient(e,y)t
ime(e, now)aspect(e, .....)
39Extending DRT Typed variables
- Types entities/objects individual oi class
oc - events individual ei class
ec
xoi, yoi, eei
gat(x)peix(y)menjar(e)agent(e,x)patient(e,y)t
ime(e, now)aspect(e, .....)
40Extending DRT Typed variables
Types entities/objects individual oi class
oc events individual ei
class ec
xoi, yoi, eei
gat(x)peix(y)menjar(e)agent(e,x)patient(e,y)t
ime(e, now)aspect(e, .....)
BUT WHAT ABOUT ENTITY AND EVENT CLASSES???
41Extending DRT Typed variables
According to Hypothesis 1 every individual
presupposes the existence of its corresponding
class. So the problem is parallel to Van der
Sandts presupposition accommodation.
- Types entities/objects individual oi class
oc - events individual ei class ec
xoi, yoi, eei
gat(x)peix(y)menjar(e)agent(e,x)patient(e,y)t
ime(e, now)aspect(e, .....)
42Extending DRT Typed variables
- Types entities/objects individual oi class oc
- events individual ei class ec
xoi, yoi, z1oc, z2oc, eei, fec
gat(x) instance(x,z1)peix(y)
instance(y,z2) menjar(e) instance(e,f)
agent(e,x)patient(e,y)time(e, now)aspect(e,
.....)
43Accessibility and Non-identity revisited
- (3) a) Every linguist discusses a donkey
sentence b) Linguists LIKE bgdonkey sentences
44Accessibility and Non-identity revisited
(3) a) Every linguist discusses a donkey
sentence
- (3) a) Every linguist discusses a donkey
sentence b) Linguists LIKE bgdonkey sentences
- (3) a) Every linguist discusses a donkey
sentence b) ok Donkey sentences are beautiful
b) ok Linguists LIKE bgdonkey sentences
x
y
linguist (x)
donkey_s (y)discuss(x,y)
45Accessibility and Non-identity revisited
(3) a) Every linguist discusses a donkey
sentence
- (3) a) Every linguist discusses a donkey
sentence b) Linguists LIKE bgdonkey sentences
- (3) a) Every linguist discusses a donkey
sentence b) ok Donkey sentences are beautiful
b) ok Linguists LIKE bgdonkey sentences
Typing of the variables Introducction of classes
via presupposition accomodation
xoi, c1oc
yoi, c2oc
linguist (x) inst(x,c1)
donkey_s (y)discuss(x,y) inst(y,c2)
46Accessibility and Non-identity revisited
(3) a) Every linguist discusses a donkey
sentence
- (3) a) Every linguist discusses a donkey
sentence b) Linguists LIKE bgdonkey sentences
- (3) a) Every linguist discusses a donkey
sentence b) ok Donkey sentences are beautiful
b) ok Linguists LIKE bgdonkey sentences
c1oc, c2oc
Projection into a higher DRS
Xoi
yoi
linguist (x) inst(x,c1)
donkey_s (y)discuss(x,y) inst(y,c2)
47Accessibility and Non-identity revisited
(3) a) Every linguist discusses a donkey
sentence b') Linguists LIKE bgdonkey
sentences
- (3) a) Every linguist discusses a donkey
sentence b) Linguists LIKE bgdonkey sentences
- (3) a) Every linguist discusses a donkey
sentence b) ok Donkey sentences are beautiful
b) ok Linguists LIKE bgdonkey sentences
c1oc, c2oc, v, w
linguists(v) wc2donkey_s(w) like(v,c2)
Xoi
yoi
linguist (x) inst(x,c1)
donkey_s (y)discuss(x,y) inst(y,c2)
48Advantages
- The non-identity problem is solved, as well as
the accessibility problem - IS resolution only needs a logical form of the
discourse. Interpretation does not influence IS.
IS does not depend on truth.
49Contrastive foci
- What about contrastive foci?
- (13) a. John insulted Bill
- b. Then BILL insulted JOHN
- The problem is that all elements in () are
anaphoric
50Contrastive Focus Layer2?
- In Bott (2004) (my PhD Thesis proposal) I
proposed a backoff model for IS resolution - 1) Simple foci can be directly linked to the
referential status of the referents contained
within this focus by the fact that these
referents cannot be discourse old and discourse
accessible. The same is true for the background
of those simple foci. I will call such foci layer
1 foci, in order to avoid implications that terms
as presentational would bring about. - Â
51Contrastive Focus Layer2?
- 2) All foci that cannot be directly determined by
the simple referential status are receive
contrastive or parallel reading. Such foci
involve relational information between discourse
referents and must, hence, be interpreted on a
compositional semantic level. I will argue that
such foci will necessarily depend on semantic
relations, but such relations are not necessarily
whole propositions. I will call such foci layer 2
foci.
52Contrastive Focus Layer2?
- In simple words
- First Try to find an anaphoric antecedent for
each word and mark every word with an
antecedent as background. - If this leads to sentence without focus, back off
into layer2 - Layer2 uses information about argument
realisation for each predicate.
53Contrastive focus and event semantics
- (13) a. John insulted Bill
- b. Then BILL insulted JOHN
- Context representation (event class domain)
arg1(e, john')
insult(e)
arg1(e, john')
insult(e) arg1(e, john')
arg1(e, john') arg2 (e, bill')
insult(e) arg2 (e, bill')
insult(e) arg1(e, john') arg2 (e, bill')
54Contrastive focus and event semantics
- (13) a. John insulted Bill
- b. Then BILL insulted JOHN
- Backgrounding
- Pruning out impossible antecedents
arg1(e, john')
insult(e)
arg1(e, john')
insult(e) arg1(e, john')
arg1(e, john') arg2 (e, bill')
insult(e) arg2 (e, bill')
insult(e) arg1(e, john') arg2 (e, bill')
55Contrastive focus and event semantics
- (13) a. John insulted Bill
- b. Then BILL insulted JOHN
- Backgrounding
- Pruning out impossible antecedents
arg1(e, john')
insult(e)
arg1(e, john')
insult(e) arg1(e, john')
arg1(e, john') arg2 (e, bill')
insult(e) arg2 (e, bill')
insult(e) arg1(e, john') arg2 (e, bill')
56Contrastive focus and event semantics
- (13) a. John insulted Bill
- b. Then BILL insulted JOHN
- Backgrounding
- Pruning out impossible antecedents
insult(e)
57Contrastive focus and event semantics
- (13) a. John insulted Bill
- b. Then BILL insulted JOHN
- Backgrounding
- Only insult will be backgrounded
insult(e)
58Backoff (Layer2) or pure event semantics?
- (13) a. John insulted Bill
- b. Then BILL insulted JOHN
- ProblemIn the entity individuals domain John and
Bill will be activated after a) has been uttered - Bill and John should be backgrounded in b)
59Backoff (Layer2) or pure event semantics?
- (13) a. John insulted Bill
- b. Then BILL insulted JOHN
- Solution1 Only event semantics (the event type
domain) is relevant for IS resolution
60Backoff (Layer2) or pure event semantics?
- (13) a. John insulted Bill
- b. Then BILL insulted JOHN
- Solution2 A backoff model
- Principle of focus requirement
- ALL SENTENCES MUST HAVE A FOCUS
61Backoff (Layer2) or pure event semantics?
- (13) a. John insulted Bill
- b. Then BILL insulted JOHN
- Solution2 A backoff model
- If all elements in the a sentences have an
antecedent, the sentence is left without a focus
and backgrounding will only take place on the
basis of the event type domain
62Evidence against the pure event semantics
solution
- (14) Q Did you see John?
- A John is working in Leeds now.
- Would we like to analyze John as part of the
focus in the answer?
63Evidence against the pure event semantics
solution
- (14) Q Did you see John?
- A John is working in Leeds now.
- Would we like to analyze John as part of the
focus in the answer?
Representation of the context (the event class
domain) see(e) agent(e, you') patient (e,
john') Qu(e) This implies the partial events
see(e) agent(e, you')see(e) patient (e,
john')..patient (e, john')
64Evidence against the pure event semantics
solution
- (14) Q Did you see John?
- A John is working in Leeds now.
- Would we like to analyze John as part of the
focus in the answer?
answer . agent(john)
Representation of the context (the event class
domain) see(e) agent(e, you') patient (e,
john') Qu(e) This implies the partial events
see(e) agent(e, you')see(e) patient (e,
john')..patient (e, john')
65Evidence against the pure event semantics
solution
- BUT, there is an interesting observation we can
make (but probably I am wrong) - In such cases the anaphoric element can
probably not be a tail (r-dislocated in catalan),
although it is probably a link (l-dislocated) - (15) Q Que lhas vist a en Joan?
- A ?Ara viu a Leeds, en Joan.
- A En Joan, ara viu a Leeds.
66Why is does NL mark topics?
- (16) Després hi ha els que sofereixen A mi
mhauries de fitxar, Buenafuente! Jo sà que ten
explicaria, dhistòries! - Buenafuente, cited in Mayol (2002)
- Tentative answer If a topic is not really
anaphoric to the discourse context, a
syntactically (phonologically, ) marked topic
will trigger presupposition accommodation.
67(some) References
- Bach, Emmon (1986). The algebra of events
Linguistics and Philosophy 9, 5-16. - Parsons, Terence (1990) Events in the semantics
of English A study in subatomic semantics.
Cambridge, MIT Press. - Carlson, Greg N. (2001) Weak indefinites. In
Coene, Martine and Yves Dhulst (eds.) From NP to
DP, 195210. (http//semanticsarchive.net/Archive/
WNhNDdiZ/Indefinites.pdf) - Steedman, M. (2000) The Syntactic Process. MIT
Press, Cambridge, MA. - van Deemter, K. (1993) What's New? A Semantic
Perspective on Sentence Accent. Journal of
Semantics 11, 1993, pp.1-31. - Van der Sandt, R.A. (1992) Presupposition
projection as anaphora resolution. Journal of
Semantics 9 333- 377. - Zuo Y. W. Zuo (2001) The Computing of
Discourse Focus. Lincom Studies in Pragmatics 6.