Breaking Down Rhetorical Relations for the purpose of Analysing 
Discourse Structures 
Jun'ichi FUKUMOTO* ,\]un'ichi TSU,1II \[ 
Centre for (~omI)utationa.1 l,inguistics, UMIST 
P.O.Box 88, Malmhcstcr M60 1QI), United Kingdom 
E-mail jun(\[~ccl.umist.ac.uk tsttjii~ccl.ulnist.ac.uk } 
Abstract 
In R, hetorical Strue(;ure Theory (RST) the detinitions 
of some rela|,iotts are rather w~gue because they are 
given on a pragmal, ic 1)asis. 'Fhis pal)er presents an- 
<>\[her way of seeing the. relations which leads to a 
more precise specification of the relations. 'l'\]m re.la: 
\[ions are associated with constrailg;S on the semantic 
relationships between tile proposit, iomd contents of two 
clauses, t,heir Modality and Tense/Asl>eet. 
1 Introduction 
The lthetorieal Strucl;ure The(,ry (lIST) by Mann and 
Thompson \[Manu and Thoml)SOn , 1.<)87\] is a t;hcory 
of int,er-s<ml,eni,ial (or inter:clausal) )'elationships in a 
text. All;hough RS'\[' is int;ended to serve both as a 
framework for taxi, analysis and l,ext generation, it has 
so flu' been used exclusiw~ly in |;exl, generation \[Hovy 
et al., 1992} \[Linden et al., 1(,)92\] \[Ri;sner and Stede, 
i992\]. Several resea.rehers recognise that RST has de- 
%ors as an analyti<:al frame.work. Moore and Pollack 
\[Moore and Pollack, 19921, for example, claim that the 
assmul)tion of a single relation bel.ween discourse el- 
CIIICtL|,S is Olle <)\[" I,he reasons why lIST analyses are 
inherently ambiguous. They also claim that the under: 
s\[)ecilieil,y of the rhel;orieal relal,ion delinil,ions causes 
problems, 
Our elaim is thai, the main cause ()17 I,he di\[liculties of 
applying liST t;o t;exl; i)rocessing systems is that SOlile 
of the relat;ions are delined on the basis of l;he elfeets 
which they have OIL a reader, This is particularly the 
case for the relations classitied as prcseulatioual rcla- 
lion.s, the relal;ions whose intended etfects are to in- 
crease some inclination in a reader. 
I),ackgrotmd relatiolh for examph;, is defined as a 
relation whose Satellite increases the al)ility of a reader 
tO (;()lLll)reh(~lld all elelnelll, in Nucleus and the reader 
will not tully comprehend Nucleus before reading the 
t,ext; of Satellite, This delinition is problematic because 
there are many ways of increasing the ability of a reader 
to comprehend Nucleus. More seriously, \[,he delinition 
*Supporte.d by Old Elcctri(: Industry Co., btd. 
itself does not predict anything about textual forlus of 
Nucleus and Satellite. 
In order to use RST in actual text processing sys- 
tems, we have to break down st<('.h detinitions to re- 
late them with I,extual forms. In this paper, we show 
how the defitfitions can be broken down and be ass()- 
eiated wil;h semaul;ic consl;raints betweell eonstituelg,S 
(clauses), in order t,o relate them with constraints on 
surface linguisl,ic forms. Among tile 24 rhetorical rela- 
tions detined in \[Mann and Thompson, 1987\], we focus 
on presentational relations (7 relations are elassilied as 
such) which are the most prol)lematic. The re.suits of 
al)plying our met;hod t<) leading ari;icles in a aal)anesc 
newspal)er are also discussed. 
2 Basic Framework 
In RST, 24 relations are divided into two groups: pre- 
s<ntational relations and subject matter rchdious. Ac- 
cording to Mmm and Thomps(m \[Malta and Thomp- 
son, 1987\], subject matter relations are those whose 
intended effect is that the reader recogldses the rela- 
l;ion in question and presentational relations are those 
whose intended eft'cot is to increase some inclination 
in the reader. Moore and Pollack \[Moore and Pollack, 
1992\] eotllllletll, i;hai; subject matter relations are infof 
mational and l)resentat,ional relations are intentional. 
Table 1 shows what kind of inclination each presen- 
tational relation is inI;ended to increase. One can see 
that tile detinitions are highly abstract and have not,h- 
ing to do with the surface realisations of the relations. 
On the other hand, it has been observed that there 
are wu:ious surface cues in texts which are useful 
\[or ideld;ifying inl;er-senl, enl;ia\[ (or inter-clausal) units. 
Ilalliday and llasan \[llalli(lay and llasan, 1985\] iden- 
titled a set of linguistic devices for linking one part of 
a text 1,o another, such as reJcrcnce, subslihtlion and 
ellipsis, conjuncliou, and \[exical cohesion. 
From the view point of text processing, these linguis- 
t, it devices can be used as cues tor segment.ing a text 
into structural units (Satellite and Nucleus). However, 
these cues hardly give any clue about which clause of 
a unit is Satellite, which clause is Nucleus, and which 
1177 
Table 1: RS 
relation 
Background 
1,hiablement 
Motivation 
l,;videnee 
Justify 
Antithesis 
Colleessiolt 
relations and their iuclination type 
ldnd of inclination 
ability of R to comprehend an element 
potential ability to perlbrm action iu 
N desire to perforln action in N 
belieJ' of N 
readiness to accept writer's right in N 
positive regard for situation presented 
in N positive regard tbr situation presented 
in N 
RS relation combines the two clauses into a single unit. 
For determining these, we have to look for other kinds 
of surface cues. 
Because RS relations are delined pragmatically, their 
ultimate recognition requires understanding of texts 
which in turn requires detailed knowledge about the 
world. Furthermore, the condition that the presenta- 
tional relations are inherently intcutioual, implies that 
their recognition requires knowledge about the writer's 
intention, l)lans, etc Because this kind of information 
is implicit in texts, its recognition often causes proh- 
lelns. 
Ilowew, r, though the writer's intention is implicit, 
certain linguistic devices give us chtes to infer it. 
Modality inforntation in a clause, for example, ex- 
presses the writer's attitude, toward an event/state de- 
scribed, attd therefore, often gives us clues to recoguise 
a I{S relation. 
Let us consider the following two examples: 
\[Example 1\] 
(1) I prepared documents for a meeting. 
(2) I sent them to the head ol\[ice. 
\[Example 2\] 
(1)' 1 am preparing documents tbr a meeting. 
(2)' 1 have to send them to the head office. 
Though these two examples describe pairs of similar 
events, the relation between (1) and (2) in l~3xample 1 
is (temporal) Sequence (a subject matter relation) be- 
cause they simply describe two events which happened 
in sequence. On the other hand, in l~3xample 2, (l)' 
describes an event occurring simultaneously with the 
utterance, and (2)' concerns what the writer plans to 
do. While the two events, preparing documents and 
sending them, may halH)0.n in this sequence, the rela- 
1;ion is not regarded as Sequence but as Background. 
(2)' gives the reason why the writer is perfomling the 
action described by (l)'. 
This change of I{.S relation occurs due to the dif- 
ference of ,nodality of (2) and (2)'. Our basic elai,n 
in that, though they cmmot determine RS relations 
uniquely, inlbrmation of modality and tense of clauses 
imposes significant constraints on possible I{S rela- 
tions, and, being used together with other surface cues 
like clausal conjunctions, it; Call reasonably restrict a 
set of possible discourse structures of texts without re- 
sorting to detailed knowledge about the world mid the 
writer's plan. 
IIowever, the contribution of modality and tense to 
the constraints of RS relations is uot straightforward. 
Both these granunatical \[i~'atures are intertwiued with 
the propositional content of clauses. There\[ore, in of 
der to formulate the co~,straints on them properly, we 
have first to reveal how the intended effects of RS re- 
lations can be attained. This leads to our breaking 
down single RS relations into sets of subschemas, each 
of which is formulated in terms of the semantic re- 
lntionshil)s between propositional eontents of clauses, 
their modality and temporal relationshil)s. 
3 Properties of Clauses 
Like Mann and Thompson, we use clauses as the ba- 
sic constituents which are related by RS relations, ex- 
cept that clausal subjects and completneuts and re- 
strictive relative clauses are considered parts of their 
host clause. The constraints which we formulate for 
each RS relation are exl)ressed in terms of propcrtic,s 
of clauses. In order to express these eonstra.ints tbr- 
really, we first introduce the l)asic terms. 
3.1 Contents and Modality 
A clause comprises its Contents and Modality. Modal- 
ity is the part which expresses the writer's attitude 
toward the Contents. 
While individual languages have their own linguistic 
devices or grmmnatical forms of modality, what sorts of 
modality are exl)ressed by such linguistic devices does 
not vary from one language to another. For example, 
although the major linguistic device for nlodality are 
modal auxiliary verbs both in l,'mglish anil in Japanese, 
some kinds of modality expressed in Japanese by modal 
auxiliary v('.rt)s are expressed by lexical verbs in En- 
glish, and vice versa. 1 
Furtherntore, we find nla, ny phrasal or quasiq)hrasal 
expressions which consist of several words, and which 
collectively express the writer's attitude toward lhe 
event/state described. In order to treat them, we 
adopt a semantics-based view tbr the delinition of 
Modality. That is, we treat expressions which concern 
the writer's attitude as modal expressions, whichew;r 
linguistic forms they may take. We \[irst establish a 
classification schema of Modality based oH semantic 
considerations (See Section 3.3) and then treat all ex- 
pressions whose functions can be classified under this 
schema as modal expressions. 
1The concepts expressed 1)y E;nglish lexlcM verbs like wish, 
hope, be!l, urqe, etc., for exmnple, ave often expressed by lnodal 
auxiliaries in .\]apanese, when the subject is Ihe writer or speaker. 
1778 
(/<intents <)f a clause is delined as the part which 
relna.ills aft, el; r(:lllOV0,l of |;be \[llod\[ll ex|)uessiOll. (~oll- 
tents COll\[,aiIl exl)ressi(>ns COilcerllillg t.ellSe gild aspect;, 
which also cont.ril>ute l;o I,he specification of constraints 
on RS relations. The same discussion as the above can 
be applied to Tense and Asl)ec|: , so that all expres- 
sions whose timer|on is to express tenq)oral aspects of 
chmses are, regar(llessly of their actual forms, treated 
in tim same classilication schemas. Tense/Aspect are 
represented as properties of (k)nl;eni.s (See Section 3.2). 
3.2 Properties of Contents 
Conl;ents is the tnaitl part of (?l;ntse of which a truth 
wtlue can be esl, ablished. (1onl,ent.s is characl, erised by 
l,hree al;l, ril)ut, es: 7!qpc, Time and Quality. 
(a) Type 
The truth value of Contents changes according to 
the time axis. We can think of two time points, 
1, and tb, where the Contents C is true during 
the time interval between t, and t~. l)epending 
<m the t, eInporal nal;ure, we classify, Conl, elltS into 
the tbllowing four classes. 
• Slalic 
t, -- undef, tl, - undef, (/(t) = t;rue 
(1. < t < / 0 
• I)wralivc 
1, = de.f, tl, = def, C(I) = t,r,te 
(t. < +. < l,,) 
• Repetitive 
1,, = def, tl, =- del!, (/(ti) = true 
(t a "< it -( t 2 <~ ..t i < ,.. < I u <~ lb) 
• No~-rcpetitivc 
l,, -- def, tb :- def, CT(ti) :- true 
(i = 1; t. < t~ < tb; l,, +- it, ) 
In the above, l,t/b -= under in SI,al,i(: means that. 
the i;rul.h wdue of (~olltelll.S does not; change. 
(b) Time 
The temporal nature of C, ontenl,s is also classified 
in terms of the speech time, 7's, as tblh)ws. 
• HeJbre : 7's < l,, 
• Simultaneous : t. < J~ < tl, 
• After : tl, < 7~ 
We llse the fi.)llowing nol;al;ion 1;o specil~y a tem- 
poral relationship hetween two Coul,enl.s (Cl and 
c~). 
Ct <2< Cu ... CI occurs before Cu 
Ct >> (/u '" Ct occurs after C2 
((') (~uality 
(\]oIll;ellt;S is also class|lied according to whether l;he 
writer believes it; is good or bad. This classillcw 
tiou is represented by the attribute Quality (qty) 
whose vahle is either good or bad. "~ 
3.a Properties of Modality 
Concerning modality, a number of criteria have been 
prol>osed. Palmer \[l'ahner, 198(i\] took the same 
semald;ics-based view of Modality as we discusseJ\[ in 
Section 3,1, though he hardly extended his analysis to 
cover l)hrasal <)r quasi--phrasal expressions. We adopt 
his <:lassitication scltema and modify it. lie class|lied 
modality into Epistcmic modality and l)c.outic modal- 
ity. Epistmnic Modality is concerned with language as 
intbrmation, with the expression of the degree or m~ 
ture of the writer's commit, ment I;o the truth of whal; 
s/he says. I)eontic modalii,y is concerned with lan- 
guage as action, mosl;ly wil.h the expression by the. 
writer of his/her attitude l,owards l>ossil)le ael,iolls hy 
him~herself and others, 
3.3.1 Epistemic modality 
Epistemic modality is class|lied according to l.hc degree 
of the writer's commil.menl; 1.o I,he I.rul, h of Conl;enl.s, 
as \[bllows. 
l,)vidc nlial ( M-ep,:,,i ) 
The truth condition of ('(ml,enl;s is based on evi- 
dence like sensory evidence or linguistic evidence 
ConJidenlial (M-ep,:o,J 
The truth condition of Contents is based on tJm 
degree of confidence expressed by the writer. 
lnfercnlial (M-epi,~l) 
The truth eondil,i(m of (~Olfl,elfl, s is based Oil a I'e;l-- 
soning rnle of the wril.er and inferred from the 
other \['a (:t.s. 
A ssu mp tivc (M-cp ....... ) 
The l;rui,h condition of Cold;cuts is I>ased on some 
assttml) l.ion. 
'Fhe degree of the writer's eolmnitment to the (,ruth 
1,ecomes weaker m the order of l,;vident.ial, Cotdiden 
tial, lnti,rential, Assumptive. In the following sections, 
we use "~" and "~" to indicate this ordering. 
means that the degre.e of the writer's commil,me:nt to 
the truth (>f (Jontenl.s C'~; is higher than or equal I.o 
the degree of the wril,er's commitmenl, to the (.rlll.h of 
(~ont.enl;s (/.v. 
2When the writer does not, think that hls/her judgement is 
obvious for readers, s/he usually exl)resscs tl m ju(!genmnl; by 
Mudality. Thcrefi:a.e, riffs attrilmte has a wdue only when 1he 
jtt(|g(:lttent c&ll be. made hased on COlllIllOH S(:\[IS(~ kllow}.edg(L 
1179 
3.3.2 Deontie modality 
Deontie modality is classified according to the kind of 
a writer's attitude which s/he expresses. 
• Evaluative (M-de+,,a+, M-de ..... ) 
EvMuative expresses the writer's attitude towards 
what s/he already accepts as trite in his/her mind. 
There are two kinds of attitude; positive ('+') and 
negative ('-'). 
• Volilive (M-de,,ot+, M-de~ot_) 
Volitive is concerned with a possible action or situ- 
ation which a writer is hopiug or wishing to occur. 
There are two kinds of attitude; possible (%') and 
impossible ('-'). 
• Directive (M-dedir) 
Directive is concerned with an action which a 
writer tries to gel others to perform. Though 
Directive is fiu:ther classified into Permission and 
Obligation, their distinction is not relevant for our 
purpose. 
• Commissive (M-de ..... ) 
Commissive is concerned with an action which a 
writer commits him/herself to perform or to ell- 
sure that an event takes place. 
• Reques~ (M-der~q) 
Request is concerned with an action which a writer 
(:an ask others to do. 
3.3.3 Combination of Epistemie and Deontie 
modality 
In l)eontic modality Ewfluative and Volitive are con- 
cerned with a writer's attitude toward Contents whic\]t 
has a truth value. Therefore, clauses with these modal- 
ities can also have Epistemic modality. If a clause has 
any of the other values of Deontie modality like Di- 
rective, etc., the Clause has no El)istemie modality as 
such. floweret, for the sitnplicity of formulation in See- 
tion 4, we assume their Epistelnic modality value to be 
Confidential .:3 
4 Breaking Down of Rhetorical 
Relations 
In this section, we will show how Background, Enable- 
ment, Motivation and Evidence of the presentational 
relations are broken down into subschemas, and give 
forlnal representations of their constraints. The colt- 
straints comprise 
(a) Semantic Relationships between Contents of the 
two clauses 
(b) Constraints on Time 
3This is not inappropriate because it is considered that a 
writer COltltnits the action in the Clause with full confidence in 
his/her action. 
(c) Constraints on Modality. 
(b) and (e) are expressed by using a characterisation 
of clauses of Section 3. We first show the framework 
for (a) and then give the actual breakdown of presen- 
tational relations. 
4.1 Semantic Relations 
By semantic relationships between Contents we mean 
the relationships between states/actions/events de- 
scribed by Contents in the extra-linguistic world. 4 As 
we nee ill Example I and 2, even when two actions seem 
to stand in the same semantic relationship, they can 
be used to attain dilferent effects on a reader by adding 
different expression of a writer's attitude as Modality 
or putting them in ¢lifferent temporal relationships. 
We classify semantic relationships into five cate- 
gories, four of which also are subject matter relations 
in RST. That is, if two Contents are presented without 
any Modality, they stand in the corresponding subject 
matter relations. We use the following symbols in their 
definitions. 
Cli : Clause i composed of Contents and Modality 
C i : Coutents of' Clause i 
Si : Contents of Clause i whose Type is Static 
Ai : Contents of Clause i whose Type is not Static 
Mi : ModMity in Clause i 
\[Semantic Relations\] 
A/~ causes a situation change froln b'i to Sj. If a 
Contents states that Ak causes a situation ,5'j, Si 
will be omitted. 
• & I = ct~ 
Clj is held true or acceptable m the environment 
stated in N. If Clj expresses a situation, this 
relation is the same as Circumstance. 
• ,5'i ~- CIj 
Clj is held true or acceptable, if ,5'i is true. If CIj 
expresses an action caused by El, this relation is 
the same as Cause aud Result. 
• 5i ~> Aj 
Si has the possibility to resolve the problem stated 
in Aj. This relation is the salne as Soluliouhood. 
• ci~cj 
Ci presents additiouul details about Cj or is in- 
ferentially accessible in Cj in one or more ways. 
This relation is the same as Elaboraliou. 
4 One may argue that such relationships have to be called 
pragmatic, ttowever, we adopt a rather narrow definition of the 
ternt praflmatic and a broad definition of the term semantic. 
We llSO, tn'agr~atic ollly when it co(lcertls effects Oli. Feadel's or 
the intention of the writer. The rest, like relationships held in 
the extra-llnguistic worhl, are called *emantic issues. 
1180 
4.2 Subschemas of Presentational Re- 
lations in RST 
We show breakdowns of follr l;ypical preseid, ai,ional 
relations inl, o theh: subschenias and stal,e their eon- 
sl;raints lnore |ornially. The subscripl;s of "uu" and 
"sa" nleans Nucleus alid Sal,ellite, respectiw;ly. 
4.2.1 Ba(.kgr(mnd 
1. Tiine and st)~ce situal,ions are stated by an action 
hi Sai,ellite, ~tlld Ultder l:hese sil, tlal;lons ;ill acti()rl 
in Nueleus becomes possit)h,. 
00 s,,-(A~°)~ &, .s'~ I- A .... 
(I,) A.. << A .... 
(ll,~ u I)eeolnes (,rue while D'l is true. Then, 
l, lle I, ilne o\[' Asa is I)efol:e tl,,u.) 
(e) A,<, >-- d ..... M~. m {M-ep,:vil ..... IinYl ...... } 
\[If A,, u beconies possible in the environ.- 
lileni; giwm by Asa, then the inodalit,y of A~. 
shouhl be more cei't, aiii I,han l,hal; of A,.,.) 
2. 'l'inie and space sil, ual;ion ;ire st, alied in Sai,ellite, 
and ulider t, he sil,ual,ion all acl, ion in Nll(',leus I)e- 
C(llilOS possibh< 
(.) &. I--= A .... 
(b) ,%<, << A .... 
(c) S~,, 7- A .... M.<,, 6 {M-.cp,,,,i I ...... I/nil ...... } 
3. Satellil;e lireseill,s addii, ional iilforinal;ion 1,o under- 
sl, and (JOlll,elil;s ill Nu(:leAls. 
(..) c~<,-~ cD,,, 
(b) .o 
(c) M,,a C {M.-¢F,,~,,il ...... Ii,,fl ...... }, 
M .... ~ {M-el.',:,,i I ..... Ii,, s'l ....... } 
(Both (~iauses will be understood ;in t, ruc., so 
they haw~ to haw'~ l,ruth wdue.) 
4 An actioli in Nueleus has l,he possibility to resoNe 
a, ii undesir~d)le sit,ual;ion which is caused 1)y an ae-- 
Lion ill Satellii,e. 
00 ,% -( .1,~ <, ) ~ ,S'I \['#:) : #'<'(4, A .... ~ ,<>', 
(b) A~<, << A .... 
(c) M~,< ~ {M-cv,:,.i .... } 
(Asa is ;~,11 event,, which has occurred or is oc- 
curring, or a writer is eonfident about the 
ew~nl,. A writer inl,ends t,o do A,~u t,o resolve 
~t l)robhmi ea~use(l Asa.) 
5. Nucleus st;al,es all undesiralJe sil, u~fl;hm caused 1)y 
aliol;her ulidesirabh~' sil,ual,ion slal,ed in Satellil,e. 
0') ,S'.,,\[qt:/: I><,< 4 t~ ,S',,,,\[qty : ~'<'<4 
(I,) .%,, << ,s',., 
(e) S,<, > S, .... M,, ~ {M-ep,.~d ..... I~,,s'l ...... }, 
M,,,, ~ {M-ep~,, d .... b,41 ...... } 
An action in Nuch;us call resolve an uitdesirable 
situation stated in Sal, ellitc. 
0~) ,%<,\[<#v : I,,,<4 --(A,.,)~ &\[q<,s : voott\] 
(I,) &,, << s .... 
(e) M~<, < {M-cp,,,,il .... Ii,,II ...... } 
7. An action in Nucleus is caused by a situation in 
Satellite. 
(~) ,%. I A .... 
(I,) ,%. << el ..... 
(c) ,%. _>. A ..... M~. < {M-ep~:,,q ..... ti,~/t ...... }, 
M,~,, C {M-tp<,.,i I ...... \[i.fl ....... } 
8. Based on *t sitm~t, iou which in caused by an actkm 
ill Satellite, a writer's a.t,l, il;ude sl,~ted hi Nueleus 
is a.ceepta,lde. 
(,~) ,%.'..,<, V: '::t .... o,: S.,, l= CZ ..... 
0,) no 
(,:) ,%,, >_ s,,., M.. < {M-cp.,q .... t~,,Sl ..... ), 
A4nu C {M-tic ...... i,,ollm,. I ...... i,.<:q} 
9. Based Oil a jlidgelliei/l; si~tl;ed in Sal,ellite, it 
wril,ei:~s aiA, il, ude sta.lied in Nucleus is aeeepl;able. 
(~) Cl~,< l- C/ ..... <)r (:,'l~<, t- c;I .... 
(i)) no 
(,:) :VL<, < {M-d<: ..... }, 
A'I,., ~ {M-de. ..... i~,<>tl,Url ...... I,'~v} 
4.2.2 l'\]nal flenmnt 
1. Nucleus stalx~s an aetion which will I)e perforined 
by a reade, r, and the action becomes possible by 
presenting the situation in Satellite. 
(a) ,%,, l- A .... 
(b) .%. << A... 
(When ,%a is presenl,ed, An. becomes possi- 
ble. So, l, he time of ,%. is before ,4...) 
(e) M,. ¢i {M-cp,.,,i I ....... }, M,,. G {M-dc,m.I,.~,~} 
(,%. already exists or will exist, so 3',,a has 
the possibility to ha, ve tru0~ vahle. If I%, is 
l, rue, A .... becomes possible~ ~qo, ,%. should 
be more cerl, ain titan A ...... ) 
2. Nucleus sI,~i,es an action which will be performed 
by a reader, ~md l;he acl;ion becomes possibh~ by 
presenting the sit,tmtion which is caused by an ac- 
tion in Satellite. 
(.) .%-~&<,)~ &, & F A .... 
(b) A,,, << A.., 
(c) M,. e {M-cv,;,, d .... }, M.,, e {M-dc,u,,I,,,:~/) 
1181 
4.2.3 Motivation 
1. An action stated in Nucleus catlses a good situa- 
tion stated in Satellite. It is considered that tile 
situation motivates the reader to l)erform the ac- 
tion. 
(a) So-(&,,)~ &,,, ,%,\['~0 : good\], 
actor(A ..... Reader) 
(l/) &,, << ,%,, 
(~) m.,, e {~-eV~.o,,,~,,~l ..... }, 
2. An action stated in Nucleus causes a bad situa- 
tion stated in Satellite. It is considered that the 
situation motiwttes the reader not to perform the 
action. 
(a) So-(A,.,)~ S. a, S,,,\[¢,y: b,,al, 
actor(d ..... Reader) 
(b) A .... << ,%. 
(c) M~a d {M-ep~o,qinjl ...... }, 
M,., G {M~de~.~.looqai,. I ..... l,'~q} 
3. Satellite states some attributive information re- 
lated to an action in Nucleus, and the information 
may be desirable for Reader. 
(a) &,,\[qO : qoo,q ~ A .... 
(b) no 
(c) Ms. ~ {M-ev,:< .... I~,,Vl ....... } 
4.2.4 Eviden('e 
(a) c.., I- c,., 
(h) c., < c;,,, 
(~) M,,, e {M-ev.,d, M.,, e {rv~-eV~o,,>,~} 
5 Examples 
We, will show au example of a text structure analysis. 
Figure 1 shows a sample text from a leading article 
in a Japanese newsl)a.t)er '5~ and 'l)able 2 shows the at- 
tributes of each sentence. The discourse structure of 
the sample text is shown in Figure 2. 
In this example, the following relations are analysed 
as l/resentational relations. The mm~ber attached to 
a relat;ion name shows the sul)schema number of the 
relation. 
• Background(8) between '1-2' and '3' 
Sentence 3 has Evaluative modality al)out the sit- 
uation '3' (economic crisis) and ii; is based on the 
situation of 'l--2' (drop of dollar). These satisfy the 
eonstraints of the 8th subschema of Background. 
5This article appeared in the October 300~, 1.987, meriting 
editoion of the Asahi Shirt,bun. 
61,iteral translations are nlade by the authors. 
No. 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
(A world-wide confusion in stock market afDcted 
the foreign exchange rate,) 
2 g~'b'~Nl'~Jfi,~ 1~\]',1 ,, (and exchange rates tbr the 
dollar dropped sharply.) 
regarded that the aspect of eeonomic crisis has 
been worsened.) 
@72 ~ ~ o (Disagreenmnt of iuternatioital policy is 
making the market unsettle.) 
5 t<,t/~llJj~j~-,5/c.g)~_ (to protect tile dollar) 
is high time that US should show a resolute atti- 
tude.) 
lar is the key currency,) 
8 'g U~t~q~ ~d:tct;~'. (it' US comes to a dead- 
lock,) 
9 ,~,D~-at~\[~. ~*~E~o (a bad economical influence. 
afDets all the world.) 
b/)~ 8/3~l"aVClg~ " &/~Cb a° (Other countries should 
re-solidify their cooperatiou taking this point into 
consideration.) 
(@1.987 Asahi Shimbun) 
Figure 1: Sample text 
• Background(6) between '4' and '5-6' 
Tim semantic relation is that a bad situation in 
sentence '4' (unsettle market) will be resolved by 
pertbrming an actiou in '5-6' (show a resohtl, e at- 
titude). Sentence '5-6' has 1)irective modality. 
These satisfy the consl;raints of the 6th subschema 
of llaekground. 
• Background(g) between '7' and '8-.9' 
The situation '7' (dollar is a key) is held true, 
so Contents '8-9' (effect of bad inlhmnce) is true. 
These satisfy the constraints of the 7th subsche.ma 
of llackgrou,M. 
Table 2: Attributes of sanq)le selltences 
Type Time Modality 
l)urative Belbre M-epe~i 
Non-repetitive Belbre M-ep~,,i 
Static Simult. M-de,t,,,M-ep(.o,~ 
Static Simult. M-epco, ~ 
Durative After M-ep~o, 
Non-repetitive After M-de,u,. 
Static Simult. M-ep~o~ 
Non-repetitive After M-epas m 
Durative After M-ep~.o,~ 
I)urative After M-der,. q 
1182 
1-10 
(-~, II~i"kg"°und 
l-3 4-ill 
1-2 3 4-6 7-10 
Non- \] Ilaclc~rotln(\]\[ M ol.ival,il//n 
voliti(\]nM ~ (--_.~ 5-6 
5 6 7 8-9 
8 9 
Figure 2: I)iscourse structure of the Saml)h~ text 
* MotiwLt, ion(2) bel.wee,i '7-9' and ' 10' 
,¢'Jelltctlce '7-9' states a bad situation (ell'eel of bad 
inlluence), aml the acl;ioI/ ill '10' (re-solidi\[}/ their 
coopcral, ion) has l,hc lmssibilil.y t,o clmnge Ihc situ- 
ation. The writer iv requcst.ing the other countries 
to take this actitm. These sa£isl'y the coustraints 
of the 2ml sul~schema of Motiwltiou. 
• 13aclcgromM(9) I,ctwcen '1-3' and '4-10' 
The request in '4-t0' (re-solidify their cooperi~- 
lion) iv based on the .}tldgcllleltl; eft'l-3' (~ wi'il;er's 
ewdual.ion o15 I, he ecotloluic crisis). T\[lcse satisl~z 
the const,rainl,s of the 91,h subschcn,a o1" \[lack- 
gr<mnd. 
6 Conclusion 
In this paper, we ln:OpOSC further a breakdown of the 
im~sentational relations in liST into their subschenms. 
The subschenias represeut strategies by which two 
states/actions/events which stand in certaill senmn 
tic relationships cau be used t.cJ attniu inte,ldcd eF- 
li~cts on readers By associating the definitions of the 
relations with formally stated const\]'ainl,s, these sub- 
schemas help hUllUtll analysts to recognise them in 
texts, and thus improw: lIST as an analytical tool, 
Moreover, because characterisation o\[ clatlSeS ill So(> 
lion 3, especially Modality and Tense/Aspect, are ac- 
companied hy their actual linguistic rcalisal;ions, some 
parts of the consl, raints staled ill SccLion 4 can readily 
I)e associated with texl;ual \['orms and be used \[or \[,ext 
processing systems. Although constraints on semantic 
relM;ions bel;wecn (~ont,ents can only be evahml, ed by 
refin'ence to a knowledge base, we expect that, ewm 
without constraints on semailtic rel~d, ions, the other 
constraints can be used I;o restrict a set of l>ossible 
inter-clausal sl,rltcl,/lres of texts. 
We imve detlncd four presenLat.ioual relat, ions in RS'I? 
lnore formally a.nd analysed a sample I;exl using these 
definitions. But the delinitions do not cover all the r<> 
lations iu ItST ~l, lld \[lil, vc IlOl, bcA;ll widely tested. After 
defiuing all t.he relations, wc will apply tlmm Io amdyse 
a. full range of I;exl;. 
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