Coordination as a Direct Process 
Augusta Mela 
LIPN-CNRS URA 1507 
Universit6 de Paris XIII 
93 430 Villetaneuse FRANCE 
am@uralS07, univ-par is 13. fr 
Christophe Fouquer6 
LIPN-CNRS URA 1507 
Universit4 de Paris XIII 
93 430 Villetaneuse FRANCE 
cf ~ura1507. univ-par is 13. fr 
Abstract 
We propose a treatment of coordination 
based on the concepts of functor, argument 
and subcategorization. Its formalization 
comprises two parts which are conceptually 
independent. On one hand, we have ex- 
tended the feature structure unification to 
disjunctive and set values in order to check 
the compatibility and the satisfiability of 
subcategorization requirements by struc- 
tured complements. On the other hand, we 
have considered the conjunction e$ (and) 
as the head of the coordinate structure, 
so that coordinate structures stem simply 
from the subcategorization specifications of 
et and the general schemata of a head sat- 
uration. Both parts have been encoded 
within HPSG using the same resource that 
is the subcategorization and its principle 
which we have just extended. 
(1) Jean danse la vMse et le tango 
(Jean dances the waltz and the tango.) 
(2) Je sais son gge et qu'elle est venue ici. 
(I know her age and that she came here.) 
(3) Un livre int4ressant et que j'aurai du plaisir 
& lire. 
(An interesting book and which I will enjoy to 
read.) 
(4) Je demande & Pierre son v61o et & Marie 
sa canne & p~che. 
(I ask Peter for his bike and Mary for her fishing 
rod.) 
(5) Pierre vend un v61o et donne une canne 
k p~che g Marie. 
(Peter sells a bike and gives a fishing rod to Mary.) 
We claim here that the "local combinatory poten- 
tial" of lexical heads, encoded in the subcategoriza- 
tion feature, explains the previous linguistic facts: 
conjuncts may be of different categories as well as of 
more than one constituent, they just have to satisfy 
the subcategorization constraints. 
1 Introduction 
Coordination has Mways been a centre of academic 
interest, be it in linguistic theory or in computa- 
tional linguistics. The problem is that the assump- 
tion according to only the constituents of the same 
category (1) may be conjoined is false; indeed, coor- 
dinations of different categories (2)-(3) and of more 
than one constituent (4)-(5) should not be dismissed 
though being marginal in written texts and must he 
accounted for 1. 
1This research has been done for the French coordi- 
nation et (and). 
We focus here on the coordination of syntagmatic 
categories (as opposite of lexical categories). More 
precisely, we account for cases of non constituent 
coordination (4), of Right Node Raising (5) but not 
for cases of Gapping. 
Our approach which is independent of any frame- 
work, is easily and precisely encoded in the for- 
malism of Head Driven Phrase Structure Grammar 
(HPSG) (Pollard and Sag, 1994), which is based on 
the notion of head and makes available the feature 
sharing mechanism we need. The paper is organized 
as follows. Section 2 gives a brief description of ba- 
sic data and discusses some constraints and avail- 
able structures. Section 3 summarizes previous ap- 
proaches and section 4 is devoted to our approach. 
The french coordination with el serves throughout 
the paper as an example. 
124 
2 A brief description of Basic Data 
and Constraints 
The classical typology of coordination, i.e. coordi- 
nation of constituents (1) and of non-constituents, 
hides some regularity of the phenomenon as it fo- 
cuses on concepts of constituent and syntactic cate- 
gory. 
A coordination of constituents is interpreted as 
one phrase without any gap. The constituents may 
be of the same category (1) as well as of different 
categories (2)-(3). However, this last case is con- 
strained as examplified hereafter 2. 
(2) Je sais son gge et qu'elle est venue ici. 
(I know her age and that she came here.) 
(2a) Je sais son £ge et son adresse. 
(I know her age and her address.) 
(2b) Je sais qu'elle a 30 ans et qu'elle est venue ici. 
(I know that she is 30 and that she came here.) 
(2c) *Je sais £ Marie et qu'elle est venue ici. 
*(I know to Marie and that she came here.) 
(2d) 3e demande l'addition et que quelqu'un paie. 
(I ask for the bill and for someone to pay.) 
(2e) *\]e rends \]'addition et que quelqu'un paie. 
*(I give back the bill and someone to pay.) 
In these examples, the coordinate structure acts as 
the argument of the verb. This verb must subcate- 
gorize for each constituent of the coordination and 
this is not the case in example (2c)-(2e). Note that 
modelizing coordination of different categories as the 
unification (i.e. underspecification) of the different 
categories would lead to accept the six examples 
or wrongly reject (2d) according to the descriptions 
used 3. 
Coordination of more than one constituent are of- 
ten classified as Conjunction Reduction (4), Gap- 
ping (la-lb) and Right Node Raising (5) (Hudson, 1976). 
(la) Jean danse la valse et Pierre, le tango. 
(Jean dances the waltz and Pierre the tango.) 
(lb) Hier, Jean a dans~ la valse et aujourd'hui, le 
tango. 
(Yesterday, Jean danced the waltz and today, the 
tango.) 
In the case of Gapping structures, the subject (la) 
and/or an extracted element (lb) is present in the 
two sides. The only allowed coordinated structure 
is \[Jean danse la valse\] et \[Pierre le tango\] for (la) 
and \[Hier, Jean a dansd la valse\] et \[aujourd'hui, le 
tango\] for (lb) as wh-sentences on other parts (\[la 
valse\] el \[Pierre\]or \[la valse\] el \[Pierre le langoj~ are 
impossible. 
A contrario, in the case of Conjunction Reduc- 
tions, wh-sentences as well as cliticization are al- 
2The star * marks ungrammatical sentences. 
3Apart from ad hoc modelizations. 
lowed referring to what follows the verb (as for coor- 
dination of constituents) and treating the arguments 
simultaneously on the two parts of the coordination: 
(4a) Je sais k qui demander un v~lo etune canne 
p~che. 
(I know who I ask for a bike and for a fishing rod.) 
(4b) 3e sais ~ qui les demander. 
(I know who I ask for them.) 
(4c) Je leur demande un v~lo etune canne ~ p~che. 
(I ask them for a bike and for a fishing rod.) 
(4d) Je les leur demande. 
(I ask them for them.) 
Let us remark that a comma is inserted between 
Marie and sa canne ~ p~che in case of extraction 
before el as in (lb), indicating the two sentences 
have not necessarily to be analyzed in the same way: 
(4e) Je demande £ Pierre son v~lo et £ Marie sa 
canne ~ p~che. 
(I ask Peter for his bike and Marie for her fishing 
rod.) 
(4f) A Pierre, je demande son v~lo et £ Marie, sa 
canne ~ p~che. 
(Peter, I ask for a bike and Marie, for a fishing 
rod.) 
Two structures are available in case of Conjunc- 
tion Reductions. One structure corresponds to a co- 
ordination of sentences with a gap of the verb after 
el, the other one consists in taking the coordinate 
parallel sequence of constituents as only one struc- 
ture. The previous facts argue for the second pos- 
sibility (see also section 3 for criticism of deletion 
approach). 
Last, note that gapping the verb is less compati- 
ble with head-driven mechanisms (and the comma in 
(4f) could be such a head mark, see (BEF, 1996) for 
an analysis of Gapping coordinations). It seems then 
that the structure needed for Conjunction Reduc- 
tion is some generalization of the standard structure 
used for coordination of constituents. Our proposal 
is then focused on this extension. We do not care of 
Gapping cases as their linguistic properties seem to 
be different. 
It remains to integrate Right-Node Raising and to 
extend these cases to more complicated ones. Sec- 
tion 4 includes examples of such cases and shows 
that our proposal can manage them adequately. 
3 Previous Approaches 
There exists a classical way to eschew the question 
"what can be coordinated ?" if one assumes a dele- 
tion analysis. Indeed, according to this approach 
(Chomsky, 1957; Banfield, 1981), only coordination 
of sentences are basic and other syntagmatic coordi- 
nations should be considered as coordinations of re- 
duced sentences, the reduction being performed by 
deleting repeated elements. This approach comes up 
125 
against insurmountable obstacles, chiefly with the 
problem of applying transformation in reverse, in 
the analysis process (Schachter, 1973). 
A direct approach has been proposed at once by 
Sag & al. (Sag et al., 1985) within the framework 
of Generalized Phrase Structure Grammar (GPSG), 
by (Pollard and Sag, 1994) within HPSG, and 
(Bresnan, 1986) within Lexical Functional Grammar 
(LFG). These approaches have tried to account for 
coordination of different categories in reducing the 
constraint from requiring the same category for con- 
juncts to a weaker constraint of category compat- 
ibility. Whatever the nature of subcategorization 
information may be, syntactical in GPSG, hybrid in 
HPSG, functional in LFG, two categories are com- 
patible if they subsume a "common denominator", 
in this case a common partial structure. 
Technically, the compatibility is checked by com- 
puting a "generalization" of categories and imposing 
the generalization comprises all features expected in 
the given context. For example, the context in (6), 
that is, the verb ~tre (to be), expects a predicative 
argument and both categories NP and AP are just 
predicative categories. 
(6) I1 est le p~re de Marie et tier de l'~tre. 
(He is Mary's father and proud of it.) 
However, this solution cannot be applied gener- 
ally because all coordinations have not such "natu- 
ral" intersection (see (2)). So we claim that we have 
nothing else to do but explicitly enumerate, within 
the head subcategorization feature, all the structures 
allowed as complement. 
4 Our Approach 
Our proposition involves three stages. We begin 
by formulating constraints on coordinate structures, 
then we define how to build the coordinate struc- 
tures and we end by specifying how the previous 
constraints filter through such coordinate structures. 
4.1 Constraints on coordinate structures 
In order to precisely formulate the constraints on co- 
ordinate structures, we distinguish the role of func- 
for and that of argument, where functor categories 
are those that bear unsatisfied subcategorization re- 
quirements, as it is the case in CategoriM Grammars 
(Dowty, 1988). Lexical heads (1) are functors in re- 
lation to the arguments they select and, by compo- 
sition, any expression that contains an unsaturated 
functor is a functor (5)-(7). 
(7) I1 pretend d~tester et refuse ces beaux spots 
lumineux. 
(He claims to hate and refuses these beautiful 
spotlights.) 
Arguments are the complements selected by the 
head 4. An argument may often be realized by differ- 
ent categories. For example, the argument required 
by savoir (to know) may be a NP or a Comple- 
tive: we say that the requirement is disjunctive and 
we represent the different alternatives within sub- 
categorization feature disjunctive values. An argu- 
ment specification is then a disjunction of categories. 
When the lexical head requires several complements 
(to ask somebody something), the requirement is said 
multiple or n-requirement. To the extent that dis- 
junction only appears in argument specifications, a 
n-requirement is a multi-set of simple requirements. 
The choice of set (or more precisely multiset) rather 
than list vMue for the feature SUBCAT allows us to 
account for Je demande ~ Pierre son vdlo as well as 
Je demande son vdlo ~ Pierre. Gunji (Gunji, 1987) 
makes the same choice. However our criterion can 
be formalized in a theory whose order of arguments 
obeys to an obliqueness hierarchy. 
Requirement inheritance. A functor may com- 
pose with another functor or with arguments. In 
functor-arguments composition, the resulting ex- 
pression inherits the unsatisfied requirement from 
the functor when it is not empty. For example, in 
(5), both conjuncts inherit the unsatisfied require- 
ment from their heads. Likewise the functor com- 
position inherits a requirement from the unsatisfied 
functor ~. In (7), pretend d~tester inherits the unsat- 
isfied requirement of d~tester, i.e. the requirement 
of an object. 
Adjuncts. To account for the continuum which 
exists from strictly subcategorized complements to 
adjuncts, we adopt the hypothesis suggested by 
(Miller, 1991) according to which adjuncts could 
be accorded the same status as arguments by inte- 
grating them into the subcategorization requirement 
through an optional lexical rule. That would enable 
us to account for coordination of adjuncts of differ- 
ent categories (3) as well as coordination of more 
than one constituent with adjuncts (10)-(11) below. 
Note that we may still have a special feature AD- 
JUNCT in order to distinguish adjuncts from other 
complements if necessary. Note also that these lexi- 
cal rules can be interpreted statically as well as dy- 
namicMly. In the first case, the extended lexicon is 
pre-computed and requires no runtime application. 
4In this paper, we restrict arguments to complements. 
In our HPSG encoding, they are treated in the SUBCAT 
feature. In a Borsley-like manner, we suppose a special 
feature for the subject. However, our approach can be 
generalized to subjects. 
5In functor composition, functors cannot be both un- 
saturated: ~" 1l promet de manger d sa m~re des ba- 
nanes.(* he promises to eat his mother bananas.), cf. 
the Incomplete Constituent Constraint (Pollard and Sag, 1994). 
126 
Satisfiability conditions of requirements. 
We observe here that a coordination of different cat- 
egories may appear as head complement when the 
head requirement is disjunctive and a coordination 
of more than one constituent appears when such a 
requirement is multiple. Last, functors may conjoin 
when their subcategorization requirements are com- 
patible. These observations are synthesized in one 
coordination criterion. 
The first observation is summarized in (C1) and 
illustrated in (2'). 
(C1) A subcategorization 1-requirement is satis- 
fied either by one of the disjuncts or by a coordi- 
nation of disjuncts. 
(2') Je sais son ~ge/qu'elle est venue ici / son £ge 
et qu'elle est venue iei. 
(I know her age/that she came here \[ her age and 
that she came here.) 
The second one is illustrated below, where subcat- 
egorization n-requirements are satisfied either by: 
• a series of n complements which satisfy respec- 
tively the n requirements 
(8) Je demande ~ Pierre son v@lo et sa canne 
p@che. 
(I ask Peter for his bike and for his fishing 
rod.) 
• a coordination of a series of this kind 
(9) Je demande & Pierre son v@lo et ~ Marie 
d'ofl elle vient. 
(I ask Peter for his bike and Mary where she 
comes from.) 
• a coordination may concern sub-series of argu- 
ments 
(10) Pierre a achet@ un livre & Marie et 
un disque £ Pierre pour 100F. 
(Peter has bought a book for Mary and a CD 
for Peter for 205.) 
• or sequences of more than one constituent with 
adjuncts (11) 
(11) J'ai vu Pierre hier et Marie lundi. 
(I have seen Peter yesterday and Mary 
monday.) 
• or adjuncts of different categories (3). 
(3) Un livre int@ressant et quej'aurai du 
plaisir £ life. 
(An interesting book and which I will enjoy 
to read.) 
All these situations are summarized in (C2): 
(C2) A subcategorization n-requirement is satis-\] 
fled by m arguments,0 < m < n~ either by a se- \[ 
quence of m arguments such That each argument \[ 
satisfies one and only one element of the require- I 
ment or by a coordination of such sequences. The I 
result has a n -- m requirement. \] 
Coordination criterion : satisfying and im- 
posing requirements. As an entity can be both 
functor and argument (12)-(13) our coordination cri- 
terion (necessary condition) is the following one: the 
conjuncts must satisfy the same simple or multiple 
subcategorization requirement and impose compati- 
ble subcategorization requirements. 
4.2 Computing the subcategorization 
requirements compatibility 
We have now to define an extension of the usual 
unification U of structures in order to compute the 
subcategorization requirements compatibility. This 
extension is an internal operation over the subcate- 
gorization requirements which accounts for disjunc- 
tive and set values. U is the unification of argument 
specifications defined from U, U + is its extension to 
n-requirements. 
• Unification of two argument specifica- 
tions ~ and/3. 
Let us have c~ = Vk=l...p sk, t3 = Vl=l...q tz, with 
categories s~, tt, then 
aU/3 =V~,t sk U tt for k, l s.t. sk U tl exists 
undefined if sk tJ tt does not exist, Vk, l 
• Unification of two n-requirements ~ and 
~. ¢ = {o, li e \[1, n\]} and ~ = {/3,1i e \[1, n\]} 
be 2 n-requirements, where al and /3/ are ar- 
gument specifications, the extended unification 
//+ of • and @ is defined if there exists a per- 
mutation p on \[1, n\] such that alU/3p\[i\] exists 
Vi E \[1, n\]. In this case ~U+@ = {ai/g/3p\[i\]/i E 
\[1, n\]) else ~L/+~ is undefined. 
Note that (C1) and (C2) should be computed si- 
multaneously in order to account for structures as 
(9). The notion of partial saturation in (C2) allows 
us to account for coordination of sub-series of argu- 
ments as in (10). 
~hnctors coordination and compatibility of 
requirements. Functors may be simple (1), com- 
posed (7), of different structures (12) or partially 
saturated (13)-(5). 
(12) Je pense offrir et que je recevrai des cadeaux. 
(I think to offer and that I will receive gifts.) 
(13) Je pense recevoir de Jean et offrir £ Pierre du 
caviar de Russie. 
(I expect to receive from John and offer to Peter 
Russian caviar.) 
In all cases, when they are conjoined, they share 
their arguments: there must therefore exist at least 
one possibility of satisfying them simultaneously. In 
this case, the unification of their subcategorization 
requirements succeeds and they are said to be com- 
patible and the two functors may be conjoined. This 
unification has to account for disjunctive values. 
127 
I Two n-requirements are compatible iff their uni- I 
fication//+ succeeds. I 
We consider that conjoined functors should have 
the same valence 6. Note that the unification of two 
n-requirements is ambiguous because we may have 
several permutations which lead to success. 
4.3 How coordinate structures are built 
Until now we have just defined constraints on the 
coordinate structures but we did not mention how 
these structures are built. We want that a coordi- 
nate structure inherits features from its conjuncts 
without necessarily failing in case of conflicting val- 
ues. The generalization method (Sag et al., 1985) 
has this objective but overgenerates because the con- 
flicting values are ignored. In contrast, the use of 
composite categories (Cooper, 1991) keeps conflict- 
ing values within the connective "A". Intuitively, 
if son age (her age) is a NP and qu'elle est venue 
ici (that she came here) is a Completive, son dge et 
qu 'elle es~ venue ici (her age and tha~ she came here) 
is a conjunctive composite category NPACompl. 
The structuring of categories : composite 
and tuple of categories. We propose to extend 
the operation A to complex categories and to use 
a new connective < ... > in order to define tuple 
of categories. With these two connectives, a total 
structuring of categories is possible and all the coor- 
dinate structures may have a status. For example, 
the underlined expression in (14) will be represented 
by the structured category: (pp, \[NPACornpl\] \ LSubcat PP J/" 
(14) Je recommande ~ Pierre la lecture et 
qu'il s'inspire de la Bible. 
(I recommend to Peter the lecture and that he 
inspires himself of the Bible.) 
The extension to complex categories is not uni- 
form. Coordinate structure features are not neces- 
sarily composites or tuples of corresponding features 
from each conjunct. In fact, features which are al- 
lowed to have conflicting values will be compounded, 
whereas other features as SUBCAT must unify. This 
structuring is encoded later within the definition of 
the lexical entry of et. 
Lexicalization of the coordination rule. We 
consider, as in (Paritong, 1992), the conjunction 
et as the head of the coordinate structure. Con- 
sequently, coordinate structures no longer have to 
be postulated in the grammar by a special rule of 
coordination: they stem simply from the general 
6This condition will forbid the conjunction of e.g. 
verbs with SUBCAT lists of different lengths, but which 
would have a unification under the alternative interpre- 
tation, thus avoiding sentences like *John bought and 
gave the book to Mary, (Miller, 1991). 
schemata of the head saturation and the subcatego- 
rization specifications of the conjunction. For sake of 
simplicity, only binary coordination is treated here. 
(Paritong, 1992) accounts for multiple coordination 
as a binary structure where the comma has a simi- 
lar function as a lexical conjunction. With that one 
restriction, the tIPSG-like lexical entry of et can be: 
I Phon \et\ Synsern <\[xl,...,IMl>^<llq ..... \[Mq>lCat= \['Part <Ca,...,CM>A<C~,...,C~M> Part C1 Part C 
| |Sub,at I,,,, reart C: 1 ..... r Part elM "\] I I I''' \[S,,b,~,~ 
{}\] ' ...,t'" J \[S~,b~at ¢'~J ' 
The following LP-constraint on the lexical entry 
of et ensures the correct order of conjunction and 
conjuncts: 
\[i\] <conj < \[i'\], where i E \[1, M\], i' E \[1', M'\]. 
This LP-constraint is the minimum required to 
distinguish the two parts of the coordinate struc- 
ture. However, the functor this coordinate struc- 
ture (partially-)saturates may impose its own LP- 
constraint (e.g. an obliqueness hierarchy). In such 
a case, this LP-constraint has to be satisfied si- 
multaneously by the two sets {\[1\],...,\[M\]} and {\[lq,..., \[Mq}. 
To represent the inheritance of the complements, 
here ~M//+ff~, we use a mechanism of argument 
composition inspired by (I-Iinrichs and Nakazawa, 
1994): the conjunction et takes as complements the 
two conjuncts < C1,...,CM > and < C~,...,C~ > 
which may remain unsaturated for their comple- 
ments (\]~M and ~4, and the set (I~M/~q-(\]?~/. The 
coordination of m-tuples, as well as the coordination 
of simple conjuncts (M = 1) stems from the satura- 
tion of the conjunction eL As noted in 4.1., only the 
last element of the tuple CM (or C~) can be unsat- 
urated and be the source of inheritance. Example of 
resulting HPSG-like anMysis is given in figure 1 for 
the underlined phrase in (15). 
(15) Jean conseille k son p~re d'acheter et ~t sa 
m~re d'utiliser un lave-vaisselle. 
(Jea~ advises his father to buy and his mother to 
use a dish washer.) 
4.4 How the constraints apply on 
coordinate structures 
We have now to define how arguments satisfy dis- 
junctive and set requirements. Intuitively, if ai is 
a (possibly disjunctive) argument specification, an 
argument (possibly composite) satisfies ai iff each 
element of the composite category matches one dis- 
junct of ai. Then, if ff is a n-requirement, a tuple 
(or a coordination of tuples) of categories (possibly 
composite) satisfies ff iff each element of the tuple 
(for each tuple) satisfies one and only one argument 
specification of ft. More formally: 
128 
Phon \A son p&re d'acheter et& sa rn~re d'utiliser\ \] 
Synsern<\[1\],\[2\]>A<\[3\],\[4\]>lOat Part <PP, Oornlal>A<PP, Oornpl> \] I Subcat {NP} J J 
\[Phon \& son p&re\ rPhon \dtaeheter\ \] \[Phon \~ sa rn&re\ \[Phon \dtutiliser\ \] Part Corn I Part Corn 1 I.Syns,rntlllCattPart PP\]\] \[Sy .... \[~\]lCat\[Subea t {.,~/~}\] \] tS~ .... \[3\]ICattPa,'t PP\]\] \[Sy .... \['\]lCat\[Subcat {.~/~}\] \] 
\[Phon\et\ \[Part<PP, Compl>^<PP, Compl> \]\] 
Part PP Part Corn I \[Part PP \] \[Part Cornpl \] NP} I.s',~ .... <tll,t=l>^<t31,t'-l>tCat \[S,.,~,=a,~ {m \[S,,b,:ot {}\] ,t:~} \[S,.,b~o,: {_-Y'~'}\] ,\[31 tS,,b~at {}J ,t"4 tS,,boat {."-P}J, 
Figure 1: Analysis of d son pdre d'acheter et d sa m~re d'utiliser 
i) let a = S 1 V... V S p be an argument specifica- 
tion, and C = A~=I..., Cr be a composite category, 
then 
C satisfies ~ iff for each element of the compos- 
ite category C,there exists one 
disjunct of e that matches it 
(iffVr e \[1, z\],gl E \[1,p\]/C, US z ex- 
ists). 
ii) let • be a n-requirement s.t.: 
: v...v <,...,,< v...v 
and E be a coordination of p tuples (if p > 1) or 
one tuple (if p = 1) of composite categories C k s.t.: 
=< q,...,c, > ^...^ < > 
= A,=,. 4 t,r 
then 
satisfies ~ iff each specification ai has one and 
only one realization in each tu- 
ple of E 
(iffVk E \[1,p\], 3 a permutation rrk 
on \[1, n\]/Vi E \[1, n\] C~kti \]k satis- 
fies '~i). 
Note that these requirement satisfiability condi- 
tions allows us to account for examples such as (9). 
4.5 A Coding in HPSG 
We extend here the functor saturation schemata to 
the coordination case, within the framework of Head 
Driven Phrase Structure Grammar (Pollard and Sag, 
1994). 
A subcategorization n-requirement is satisfied 
by m arguments, m < n, either by a sequence of 
m arguments (m-tuple) or by a coordination of m- 
tuples. The result has a n - m requirement. 
Saturation schemata 7 
- partial (~ # {}) or total (~ = {}) of saturated 
complements (*' = {}) 
total (~ = {}) of complements, the last being 
partially (~' # {}) or totally saturated (~' = 
{}) 
\[Synsem,Cat\[Subcat~U~'\] \]\] Branches = 
\[B - Yead\[Synsem\[Cat\[Subcat ~ U ~\] \[B - Comp = ~\[Subcat ~'\] 
where E satisfies ~ and: 
• ¢ = {< s v...vsp >,..., < >} 
m-requirement, ~ n - m requirement 
• ~ ----< Cll,...,C 1 > A...A < C\[,...,Cqm > 
coordination of q m-tuples (if q > 1) or one 
m- tuple (if q = 1) of composite Synsem C/k = 
A,=I...~ C'~ 
• • or ~' must be empty 
Example of resulting analysis is given in figure 2 
for the underlined phrase in (15): 
(15) Jean conseille & son p@re d'acheter et& sa 
m~re d'utiliser un lave-vaisselle. 
(Jean advises his father to buy and his mother to 
use a dish washer.) 
Note that within a theory as HPSG which inte- 
grates syntactic and semantic information in a sin- 
gle representation, a whole range of lexically deter- 
mined dependencies, e.g. case assignment, govern- 
ment (of particular prepositions) and role assign- 
ment, are modeled at the same time via subcat- 
egorization because the value of subcategorization 
feature is a complex of syntactic and semantic infor- 
mation. 
r~ U ~Z is the set-union of ~ and t9 
129 
Pho. \conseille & son p~re dlacheter et h sa rn~re dlutiliser ur* lave--vaisselle\\] 
Synserc* \[VP\] J 
Pho. \ ..... ill¢ & aon p~re d'acheter et i~ 8a rn~re dtutiliser\\] \[Phon \un I ...... issel/e\\] 
Synnern IVP\[Subcat {NP}\] \[Sy.$ern \[Part NP\] J 
\[Phon \conseille\ \] \[Phon \b son p~re dtacheter et b sa rn~re dS utiliser\ \] Part V 
.... <PP, Co,.p,>',, t Subcat {NP} J J 
Figure 2: Analysis of conseille ~ son p~re d'acheter et ~ sa m~re d'utiliser un lave-vaisselle 
5 Conclusion 
This approach based on concept of functor, argu- 
ment and subcategorization allows us to account for 
many coordination data. Its formalization comprises 
two parts which are conceptually independent. On 
one hand, we have extended the feature structure 
unification to disjunctive and set values in order to 
check the compatibility and the satisfiability of sub- 
categorization requirements by structured comple- 
ments. On the other hand, we have considered the 
conjunction et as the head of the coordinate struc- 
ture, so that coordinate structures stem simply from 
the subcategorization specifications of et and a gen- 
eral schemata of the head saturation. Both parts 
have been encoded within HPSG using the same re- 
source that is the subcategorization and its principle 
which we have just extended. 
It remains to know in which extent our ap- 
proach can be used for other linguistic phenomena 
with symetrical sequences of more than one con- 
stituent (comparative constructions, Mternative con- 
structions): 
(16) Paul donne autant de couteaux aux filles que 
de pi~ces aux garcons. 
(Paul gives as much knives to the girls as coins to 
the boys.) 

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