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<?xml version="1.0" standalone="yes"?> <Paper uid="J94-4004"> <Title>Machine Translation Divergences: A Formal Description and Proposed Solution</Title> <Section position="5" start_page="600" end_page="600" type="metho"> <SectionTitle> CLCS representation for John went happily to school. </SectionTitle> <Paragraph position="0"> between the interlingual representation and the surface syntactic representation. In addition, T(~) is the logical type (Event, State, Path, Position, etc.) corresponding to the primitive ~ (CAUSE, LET, GO, STAY, BE, etc.); Primitives are further categorized into fields (e.g., Possessional, Identificational, Temporal, Locational, etc.). 4 Example 1 The LCS representation of John went happily to school is</Paragraph> <Section position="1" start_page="600" end_page="600" type="sub_section"> <SectionTitle> \[Event GOLoc (\[Thing JOHN\], </SectionTitle> <Paragraph position="0"> \[Path TOLoc (\[Position ATLoc (\[Thing JOHN\], \[Location SCHOOL\])\])\] \[M ..... HAPPILY\])\] This corresponds to the tree-like representation shown in Figure 3, in which (1) the logical head is GOLoc (of type Event); (2) the logical subject is JOHN (of type Thing); (3) the logical argument is TOcoc (of type Path); and (4) the logical modifier is HAPPILY (of type Manner). Note that the logical argument is itself a LCS that contains a logical argument, SCHOOL (of type Location), i.e., LCSs are recursively defined.</Paragraph> <Paragraph position="1"> The LCS representation is used both in the lexicon and in the interlingual representation. The former is identified as a root LCS (RLCS) and the latter is identified as a composed LCS (CLCS): Definition 2 A RLCS (i.e., a root LCS) is an uninstantiated LCS that is associated with a word definition in the lexicon (i.e., a LCS with unfilled variable positions).</Paragraph> <Paragraph position="2"> Example 2 The RLCS associated with the word go (from Example 1) is \[Event GOLoc (\[Thing X\], \[Path TOLoc (\[Position ATLoc (\[Thing X\], \[Location Z\])\])\])\]</Paragraph> </Section> </Section> <Section position="6" start_page="600" end_page="602" type="metho"> <SectionTitle> 4 The validity of the primitives and their compositional properties is not discussed here. The LCS has </SectionTitle> <Paragraph position="0"> been studied as the basis of a representation for multiple languages (see, for example, Hale and Keyser 1986a, 1986b, 1989; Hale and Laughren 1983; Levin and Rappaport 1986; Zubizarreta 1982, 1987) and is discussed in the context of machine translation by Dorr (1992b).</Paragraph> <Paragraph position="2"> RLCS representation for go.</Paragraph> <Paragraph position="3"> which corresponds to the tree-like representation shown in Figure 4. Definition 3 A CLCS (i.e., a composed LCS) is an instantiated LCS that is the result of combining two or more RLCSs by means of unification (roughly). This is the interlingua, or languageindependent, form that serves as the pivot between the source and target languages. Example 3 If we compose the RLCS for go (in Figure 4) with the RLCSs for John (\[ThingJOHN\]), school (\[Location SCHOOL\]), and happily (\[Manner HAPPILY\]), we get the CLCS corresponding to John went happily to school (shown in Figure 3).</Paragraph> <Paragraph position="4"> Each (content) word in the lexicon is associated with a RLCS, whose variable positions may have certain restrictions. The CLCS is a structure that results from combining the lexical items of a source-language sentence into a single underlying pivot form by means of LCS composition. 5 The notion of unification (as used in Definition 3) differs from that of the standard unification frameworks (see, for example, Shieber et al. 1989, 1990; Kaplan and Bresnan 1982; Kaplan et al. 1989; Kay 1984; etc.) in that it is not directly invertible. That is, the generation process operates on the CLCS in a unification-like fashion that roughly mirrors the LCS composition process, but it is not a direct inverse of this process. The notion of unification used here also differs from others in that it is a more &quot;relaxed&quot; notion: those words that are mapped in a relaxed way are associated with special lexical information (i.e., the :INT, :EXT, :PROMOTE, :DEMOTE, ,, :CAT, and :CONFLATED parameters, each of which will be formalized shortly).</Paragraph> <Paragraph position="5"> A fundamental component of the mapping between the interlingual representation and the surface syntactic representation is the syntactic phrase.</Paragraph> <Paragraph position="6"> Definition 4 A syntactic phrase is a maximal projection that conforms to the following structural form: 5 This process is described in detail in Dorr (1992b).</Paragraph> <Paragraph position="7"> Bonnie J. Dorr Machine Translation Divergences Y-MAX Q-MAXj+I ... Q-MAXk Y-MAX Q-MAXk+ I ... Q.MAX m W-MAX X-MAX X Z-MAX1 ... Z-MAX a Q-MAX 1 ... Q-MAXi X Q-MAXi+ 1 ... Q-MAXj Figure 5 Formal definition of syntactic phrase.</Paragraph> <Paragraph position="9"> This corresponds to the tree-like representation shown in Figure 5, in which (1) X is the syntactic head (of category V, N, A, P, I, or C); (2) W-MAX is the external argument; (3) Z-MAX1, ..., Z-MAXn are the internal arguments; and (4) Q-MAX1 ..... Q-MAXm are the syntactic adjuncts.</Paragraph> <Paragraph position="10"> Example 4 The syntactic phrase corresponding to John went happily to school is</Paragraph> </Section> <Section position="7" start_page="602" end_page="604" type="metho"> <SectionTitle> \[C-MAX \[I-MAX \[N-MAX John\] </SectionTitle> <Paragraph position="0"> \[V-MAX \[v went\] \[ADV happily\] \[P-MAX to \[N-MAX school\]\]\]\]\] This corresponds to the tree-like representation shown in Figure 6, in which (1) the syntactic head is \[v went\]; (2) the external argument is \[N-MAX John\]; (3) the internal argument is \[P-MAX a ...\]; and (4) the syntactic adjunct is \[ADV happily\]. Note that the internal argument constituent is itself a syntactic phrase that contains an internal argument, \[N-MAX school\], i.e., syntactic phrases are recursively defined.</Paragraph> <Paragraph position="1"> In addition to the representations involved in the translation mapping, it is also possible to formalize the mapping itself. The current approach is to map between 6 These syntactic structures are based on the X framework of government-binding theory (see Chomsky 1981, 1982, 1986a, 1986b). For ease of illustration, the word order used in all formal definitions is head-initial/spec-initial (i.e., the setting for English). The syntactic operations that determine word order are completely independent from the lexical-semantic operations that use these definitions. Thus, the formal definitions can be stated in terms of an arbitrary ordering of constituents, without loss of generality, as long as it is understood that the constituent order is independently determined.</Paragraph> <Paragraph position="2"> Syntactic phrase representation for John went happily to school.</Paragraph> <Paragraph position="3"> the LCS representation and the surface syntactic form by means of two routines that are grounded in linguistic theory: a generalized linking routine (GPST4) and a canonical syntactic realization (CST4). These routines are defined formally here: Definition 5 The ~PST4 systematically relates syntactic positions from Definition 1 and lexical- null semantic positions from Definition 4 as follows: 1. X I 4=~X 2. W'~W 3. Z I\] * * * Kin ~ Zl * .. Zn 4. Q'I--. Q'm 4=~ Q1,.. Qm Example 5 The correspondence between the LCS of Example 1 and the syntactic structure of Example 4 (i.e., for the sentence John went happily to school) is (1) X ~ = GOLoc 4=~ X = Iv</Paragraph> <Paragraph position="5"> The CST4 systematically relates a lexical-semantic type T(~') to a syntactic category CAT(h), where ~t is a CLCS constituent related to the syntactic constituent C/> by the ~PS~.</Paragraph> <Paragraph position="6"> Example 6 The LCS type Thing corresponds to the syntactic category N, which is ultimately projected up to a maximal level (i.e., N-MAX). The full range of realization possibilities is given in Figure 7.</Paragraph> <Paragraph position="7"> CST4 mapping between LCS types and syntactic categories. Now that we have formally defined the representations and mappings used during translation, we will turn to a classification of divergences that is based on these definitions.</Paragraph> </Section> <Section position="8" start_page="604" end_page="607" type="metho"> <SectionTitle> 4. The Divergence Problem: Formal Classification and Solution </SectionTitle> <Paragraph position="0"> In general, translation divergences occur when there is an exception either to the ~PST4 or to the CST4 (or to both) in one language, but not in the other. 7 This premise allows one to define formally a classification of all lexical-semantic divergences that arise during translation (i.e., divergences based on properties associated with lexical 7 Most of the examples in this paper seem to suggest that a divergence is defined in terms of a language-to-language phenomenon: a divergence occurs when a sentence in language L1 translates into a sentence in L2 in a very different form (i.e., differently shaped parse trees or similarly shaped trees with different basic categories). This definition implies that a divergence may arise between two languages L1 and L2, independent of the way the translation is done (i.e., direct, transfer, or interlingual).</Paragraph> <Paragraph position="1"> However, it is also possible to define a divergence from an interlingual point of view, i.e., with respect to an underlying representation (lexical conceptual structure) that has been chosen to describe the source and target language sentences. From this point of view, a divergent mapping may apply even in cases in which the source- and target-language pairs do not exhibit any distinctions on the surface (e.g., the translation of the German sentence Hans kuflt Marie gern as the equivalent Dutch sentence Hans kust Marie graag, both of which literally translate to Hans kisses Mary likingly). In such cases, there are generally two occurrences of a language-to-interlingua divergence: one from the surface structure and one to the surface structure. (The terms language-to-language and language-to-interlingua are taken from Dorr and Voss 1993a.) At first glance, it might seem odd to introduce the notion of a language-to-interlingua divergence for cases that do not exhibit a language-to-language divergence. However, it is clearly the case that language-to-language divergences--a special case of language-to-interlingua divergences--do exist regardless of the translation approach adopted. Thus, we can view divergences more generally as a consequence of the internal mapping between the surface structure and the interlingual representation rather than as an external distinction that shows up on the surface. The result is that the interlingua appears to have been simplified to the extent that it accommodates constructions in one language (without any special information) more readily than it accommodates the corresponding construction in another language. However, as one reviewer points out, this is not an undesirable consequence, since the development of a suitable representation is where the interlingua builder has a choice and should choose the simplest representation format. The appropriate question to ask is whether an approach that addresses the divergence problem from a language-to-interlingua perspective is an improvement over an approach that addresses the problem strictly from a language-to-language point of view. This paper argues that the language-to-interlingua approach is the correct one given that the alternative would be to handle language-to-language divergences by constructing detailed source-to-target transfer rules for each lexical entry in the source and target language. Introducing the notion of language-to-interlingua divergence allows the translation mapping to be defined in terms of a representation that is general enough to carry over to several different language pairs.</Paragraph> <Paragraph position="2"> GPSTC/ mapping between the CLCS and the syntactic structure.</Paragraph> <Paragraph position="3"> entries that are not based on purely syntactic information, idiomatic usage, aspectual knowledge, discourse knowledge, domain knowledge, or world knowledge).</Paragraph> <Paragraph position="4"> Before we define and resolve each divergence type, we will first make some revisions to the representations used in Definitions 1 and 4 to simplify the presentation.</Paragraph> <Paragraph position="5"> The representation given in Definition 1 is revised so that Z' is used to denote a logical argument from the set {Z~l ... Z~n} and Q' is used to denote a logical modifier from the set {Q'I ... Q'm}. The resulting representation is considerably simplified: (8) \[T(X') X' (\[T(W') Wt\], \[T(Z') Z'\], \[T(Q') Q'\])\] Similarly, the representation given in Definition 4 is revised so that W is used to denote the external argument, Z is used to denote an internal argument from the set {Z-MAX1 ... Z-MAXn}, and Q is used to denote a syntactic adjunct from the set {Q-MAXI ...</Paragraph> <Paragraph position="6"> Q-MAXm}. The resulting representation has the following simplified form: (9) \[Y-MAX \[Y-MAX W IX-MAX X Z\]\] Q\]8 With these simplifications, the GPST4 can be conceptualized as the following set of relations: (10) Simplified GPST4: 1. X' ~X 2. W~ ~W 3. Z' ~Z 4. Q'~Q Figure 8 shows the simplified ~PST4 in terms of tree-like representations. 9 We are now prepared to define and resolve the translation divergences of Figure 1 on the basis of the simplified formalization presented in (8)-(10) above. The 8 For the purposes of this discussion, we will retain the convention that syntactic adjuncts occur on the right at the maximal level. Note that this is not always the case: the setting of an adjunction parameter (described by Dorr \[1993b\]) determines the side and level at which a particular adjunct will occur. 9 For ease of illustration, this diagram omits the type specification. (There is no loss of generality, since the GPS'R mapping does not make use of this specification.) We will retain this convention throughout the rest of this paper.</Paragraph> <Paragraph position="7"> Translation mappings for cases in which GPS~ default positions are overridden.</Paragraph> <Paragraph position="8"> solution to the divergence problem relies solely on three types of information: the GPST4; the CST4; and a small set of parametric mechanisms. The GPST4 and C$T4 are intended to be language independent, whereas the parameters are intended to encode language-specific information about lexical items. Because the interlingual representation preserves relevant lexical-semantic relations, these three types of information are all that are required for providing a systematic solution to the divergence types shown in Figure 1. In particular, the solution given here eliminates the need for transfer rules and relies instead on parameterized mappings that are defined and applied uniformly across all languages. Seven parameters are used to invoke exceptions to the ~PST4 and C$T4 functions in the context of translation divergences: :INT, :EXT, :PROMOTE, :DE-MOTE, ,, :CAT, and :CONFLATED. We will now present a formal description of each divergence type and its associated parameter.</Paragraph> <Section position="1" start_page="606" end_page="607" type="sub_section"> <SectionTitle> 4.1 Thematic Divergence </SectionTitle> <Paragraph position="0"> The first divergence type to be formalized is the one for thematic divergence, i.e., the repositioning of arguments with respect to a given head. This type of divergence arises Computational Linguistics Volume 20, Number 4 in cases in which the ~PST4 invokes the following sets of relations in place of steps 2 and 3 of (10):</Paragraph> <Paragraph position="2"> Figure 9a shows the revised mapping.</Paragraph> <Paragraph position="3"> Thematic divergence arises only in cases in which there is a logical subject. An example of thematic divergence is the reversal of the subject with an object, as in the thematic divergence example given earlier in (1). The syntactic structures and corresponding CLCS are shown here:</Paragraph> </Section> </Section> <Section position="9" start_page="607" end_page="611" type="metho"> <SectionTitle> \[C-MAX \[I-MAX IN-MAX Maria\] \[V-MAX IV me gusta\]l\]\] 1deg </SectionTitle> <Paragraph position="0"> Here the object Mary has reversed places with the subject I in the Spanish translation.</Paragraph> <Paragraph position="1"> The result is that the object Mary turns into the subject Maria, and the subject I turns into the object me.</Paragraph> <Paragraph position="2"> This argument reversal is resolved by means of the :INT and :EXT parameters, which force the ~PST4 mapping to be overridden with respect to the positioning of the logical subject and logical argument in Spanish. The lexical entries for like and gustar illustrate the difference in the use of these parameters: Because the English entry does not include these parameters, the translation relies on the default argument positionings imposed by the ~PST4. By contrast, the :INT/:EXT markers specified in the Spanish entry force the internal and external arguments to swap places in the syntactic structure.</Paragraph> <Paragraph position="3"> 10 For the purposes of this discussion, the Spanish sentence is given in its uninverted form. There are other ways of realizing this sentence. In particular, a native speaker of Spanish will frequently invert the subject to post-verbal position: \[C-MAX \[I--MAX ei \[V-MAX IV--MAX \[V me gusta\]\] IN--MAX Mafia\]i\]\]\].</Paragraph> <Paragraph position="4"> However, this does not affect the internal/external reversal scheme described here, since inversion is a syntactic operation that takes place independently of the process that handles thematic divergences. Bonnie J. Dorr Machine Translation Divergences The general solution to thematic divergence is diagrammed as follows: (14) RLCS 1: \[T(X,) X' (\[T(W') W'\], \[r(z,) Z'\] \[T(Q') Q'\])\] RLCS 2: \[r(x,) X' (\[r(w') :INT W'\], \[T(Z') :EXT Z'\] \[T(Q') Q'I)\] Translation: \[Y-MAX \[Y-MAX W \[X-MAX X Z\]\] Q\] \[T(X') X' (\[T(W') W'\], \[T(Z') Z'\] \[T(Q') Q'\])\] \[Y-MAX \[Y-MAX Z \[X-MAX X Wll QI This assumes that there is only one external argument and zero or more internal arguments. If the situation arises in which more than one variable is associated with the :EXT markers, it is assumed that there is an error in the word definition. N Note that the :INT and :EXT markers show up only in the RLCS. The CLCS does not include any such markers, since it is intended to be a language-independent representation for the source- and target-language sentences.</Paragraph> <Paragraph position="5"> Thematic divergence is one of three types of possible positioning variations that force the GPST4 to be overridden. Two additional positioning variations are promotional and demotional divergences, which will be defined in the next two sections. Whereas thematic divergence involves a repositioning of two satellites relative to a head, promotional and demotional divergences involve a repositioning of the head itself\] 2 We will see in Section 5.1 that these three divergences account for the entire range of repositioning possibilities.</Paragraph> <Section position="1" start_page="608" end_page="609" type="sub_section"> <SectionTitle> 4.2 Promotional Divergence </SectionTitle> <Paragraph position="0"> Promotional divergence is characterized by the promotion (placement &quot;higher up&quot;) of a logical modifier into a main verb position (or vice versa), as shown in Figure 9b.</Paragraph> <Paragraph position="1"> In such a situation, the logical modifier is associated with the syntactic head position, and the logical head is then associated with an internal argument position. Thus, promotional divergence overrides the GPST4, invoking the following sets of relations in place of steps 1 and 4 of (10):</Paragraph> <Paragraph position="3"> Figure 9b shows the revised mapping.</Paragraph> <Paragraph position="4"> 11 The parameters associated with the RLCS are assumed to be correctly specified for the purposes of this formal description. However, in practice, there might be errors in the lexical entries, since they are constructed by hand in the current implementation. Eventually, the intent is to automate the process of lexical entry construction so that these errors can be avoided.</Paragraph> <Paragraph position="5"> 12 The notions of demotion and promotion are not the same as the notions of demotion and advancement in the theory of relational grammar (see Perlmutter 1983). Dorr (1993b, pp. 269-274) argues that, although the relational representation might be a convenient tool for illustrating the promotion and demotion operations as used in the current approach, this representation is not an appropriate vehicle for interlingual translation for a number of reasons.</Paragraph> <Paragraph position="6"> 13 This relation does not mean that X replaces Z (if there is a Z), but that X retains the same structural relation with Z (i.e., Z remains an internal argument of X). To simplify the current description, Z is not shown in the syntactic structure of Figure 9b.</Paragraph> <Paragraph position="7"> Computational Linguistics Volume 20, Number 4 An example of promotional divergence is the case given earlier in (2). The syntactic structures and corresponding CLCS are shown here: Here the main verb go is modified by an adverbial adjunct usually, but in Spanish, usually has been placed into a higher position as the main verb soler, and the &quot;going home&quot; event has been realized as the internal argument of this verb.</Paragraph> <Paragraph position="8"> Promotional divergence is resolved by the :PROMOTE parameter, which forces the ~PST4 mapping to be overridden with respect to the positioning of the logical head and the logical modifier. The lexical entries for usually and soler illustrate the difference in the use of this parameter: Because the English entry does not use this parameter, the translation relies on the default argument positionings imposed by the GPST4. By contrast, the :PROMOTE marker specified in the Spanish entry forces the head and adjunct to swap places in the syntactic structure.</Paragraph> <Paragraph position="9"> The general solution to promotional divergence is diagrammed as follows: (18) RLCS 1: \[T(Q') Q'\] RLCS 2: \[T(Q') :PROMOTE Q'\] Translation: \[Y-MAX \[Y-MAX W \[X--MAX X Z\]\] Q\] \[T(X') X' (\[T(W') W'\], \[T(Z') Z'\] \[T(Q') Q'\])\] \[Y-MAX \[Y-MAX W \[X-MAX Q \[ ... X Z\]\]\]\]</Paragraph> </Section> <Section position="2" start_page="609" end_page="611" type="sub_section"> <SectionTitle> 4.3 Demotional Divergence </SectionTitle> <Paragraph position="0"> Demotional divergence is characterized by the demotion (placement &quot;lower down&quot;) of a logical head into an internal argument position (or vice versa), as shown in Figure 9c.</Paragraph> <Paragraph position="1"> In such a situation, the logical head is associated with the syntactic adjunct position, and the logical argument is then associated with a syntactic head position. Thus, Bonnie J. Dorr Machine Translation Divergences demotional divergence overrides the gPST4, invoking the following sets of relations in place of steps 1 and 3 of (10): (19) 1.' X' 4:~ Q14 3.' Z' 4:> X Figure 9(c) shows the revised mapping.</Paragraph> <Paragraph position="2"> An example of demotional divergence is the case given earlier in (3). The syntactic structures and corresponding CLCS are shown here: is Here the main verb like takes the &quot;to eat&quot; event as an internal argument; but in German, like has been placed into a lower position as the adjunct gern, and the &quot;eat&quot; event has been realized as the main verb.</Paragraph> <Paragraph position="3"> The distinction between promotional and demotional divergences may not be intuitively obvious at first glance. In both cases, the translation mapping appears to associate a main verb with an adverbial satellite, or vice versa. However, the distinction between these two head switching cases becomes more apparent when we consider the status of the participating lexical tokens more carefully. In the case of soler-usually, the main verb soler is, in some sense, the token that &quot;triggers&quot; the head switching operation: its presence forces the adverbial satellite usually to appear in English, even if we were to substitute some other event for ir in Spanish (e.g., correr a la tienda, leer un libro, etc.). By contrast, in the case of like-gern, the triggering element is not the main verb like, since we are able to use like in other contexts that do not require gern (e.g., I like the car ~ Mir gefdllt der Wagen); instead, the triggering element is the adverbial satellite gern: its presence forces the verb like to appear in English even if we were to substitute some other event in place of essen in German (e.g., zum Geschdft laufen, das Buch lesen, etc.). We will return to this point in Section 5.2. Demotional divergence is resolved by the :DEMOTE parameter, which forces the ~PST4 mapping to be overridden with respect to the positioning of the logical head and the logical argument. The lexical entries for like and gern illustrate the difference in the use of this parameter: 17 14 This relation does not mean that X replaces Q (if there is a Q), but that X retains the same structural relation with Q (i.e., Q remains a syntactic adjunct of X). To simplify the current description, Q is not shown in the syntactic structure of Figure 9c.</Paragraph> <Paragraph position="4"> 15 The default object being eaten is FOOD, although this argument does not appear on the surface for the current example.</Paragraph> <Paragraph position="5"> 16 The German syntactic structure is shown here in the uninverted base form. In the German surface structure, the verb is moved up into verb-second position and the subject is topicalized: \[C--MAX IN--MAX IchJ/ Iv esse\]j \[I--MAX IN--MAX t\]l IV--MAX Iv \[ADV gem\] Iv t\]/\]\]/\]. 17 Both definitions of like in (21) use the circumstantial field, which means that the Y argument must be an Event (e.g., like ta eat) rather than a Thing (e.g., like Mary). Thus, the definitions for like and gern are slightly different from the definitions of like given earlier in (13) (i.e., these are additional lexical entries for like).</Paragraph> <Paragraph position="6"> Because the English entry does not use this parameter, the translation relies on the default argument positionings imposed by the ~PST4. By contrast, the :DEMOTE marker specified in the German entry forces the head and internal argument to swap places in the syntactic structure.</Paragraph> <Paragraph position="7"> The general solution to demotional divergence is diagrammed as follows: (22) RLCS 1: \[v(x') X' (\[T(W') W'\], \[T(Z') Z'\] \[T(Q') Q'\])\] RLCS 2: \[T(X') X' (\[T(W') W'\], \[T(Z') :DEMOTE Z'\] \[T(Q') Q'\])\] Translation: \[Y-MAX \[Y-MAX W IX-MAX X Z\]\] Q\] \[v(x') X' (\[T(W'/ W'\], \[T(Z') Z'\] \[T(Q'/ Q'\])l \[Y--MAX \[Y-MAX W IX-MAX Z\] \[ ... X QI\]\]</Paragraph> </Section> <Section position="3" start_page="611" end_page="611" type="sub_section"> <SectionTitle> 4.4 Structural Divergence </SectionTitle> <Paragraph position="0"> Structural divergence differs from the last three divergence types in that it does not alter the positions used in the ~PST4 mapping, but it changes the nature of the relation between the different positions (i.e., the &quot;4=~&quot; correspondence). Figure 9d characterizes the alteration that takes place. Note that the mapping of Z' to the corresponding internal argument position is altered so that it is positioned under the constituent that corresponds to W.</Paragraph> <Paragraph position="1"> An example of structural divergence is the case given earlier in (4). The syntactic structures and corresponding CLCS are shown here:</Paragraph> </Section> </Section> class="xml-element"></Paper>