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<?xml version="1.0" standalone="yes"?> <Paper uid="C86-1010"> <Title>Category Cooccurrence Restrictiorls and the Elimination of Metar1~les</Title> <Section position="2" start_page="0" end_page="51" type="metho"> <SectionTitle> 1. Category Cooecurrence Restrictions (CCRs) </SectionTitle> <Paragraph position="0"/> <Section position="1" start_page="0" end_page="50" type="sub_section"> <SectionTitle> I,i The Principle of CCRs </SectionTitle> <Paragraph position="0"> The reasons for proposing CCRs to state restrictions on the eooccurrence of categories within local trees are analogous to those for introducing Inmlediate Dominance (ID) and Linear Precedence (LP) rules in GPSG (of GEPS, pp. 44-50). A context free rule binds information of two sorts in a single statement, namely (a) information about which daughters a rook has in a local tree and (b) information about the order in which the daughters appear.</Paragraph> <Paragraph position="1"> By separating this information in ID and LP rules, GPSG is able to state generalizations of the sort &quot;A preceeds B in every local tree which contains both as daughters,&quot; which cannot be captured in a context free grammar (CFG).</Paragraph> <Paragraph position="2"> Now consider an ID rule such as the following: (i) S --> A, B, C The fundmnental motivation for CCRs rests on the insight that such an ID rule itself combines two different kinds of information in a single statement, namely (a) information involving immediate dominance relations, here that <S, A>~ <S, B>, and <S, C> are ordered pairs of categories in which the first category inmlediately dominates the second and (b) information about the cooccurrence of categories in a single local tree.</Paragraph> <Paragraph position="3"> By distinguishing and separately representing these types of information it becomes possible to state generalizations of the following sort, which cannot be captured in the ID/LP format: (2) Any local tree with S as its root must have A as a daughter.</Paragraph> <Paragraph position="4"> (3) No local tree with C as a daughter also has D as a daughter.</Paragraph> <Paragraph position="5"> Statements such as (2) and (3) restricting the cooccurrence of categories in local trees are Category Cooccurrence Restrictions, which are expressions of first arder predicate logic using two primitive predicates, R(cx, t) 'cx is the root of local tree t' and D(~, t) 'a is a daughter in local tree t'. \[2\] CCRs have the form Vt: ~, where 1T :is a schema and the notion of a possible schema is defined as follows: (i) (R(a, t)) and (D(~,t)) are of form g; (it) if ~ is of form g, then (~) is of form n; (iiJ) if Ip and x are both of form I~, then (~0Kr) is of form ~, where K C (A, V, D, e}; (iv) constants designating categories occur as first arguments within all coastituent predicate expressions; (v) the same variable t bound by the quantifier Vt occurs as second argument within all constituent predicate expressions; (vi) these are all expressions of form ~.</Paragraph> <Paragraph position="6"> Parentheses may be omitted following the usual conventions in predicate logic.</Paragraph> <Paragraph position="7"> A CCR Vt: u may be rewritten in conjunctive normal form as Vt: ~ ^ ... A ~ , where each clause ot posltlve and predicate <Pi is a disjunction . . n negated expressions, which is equivalent to V t: \[p\] ^ ... AVt: ~ , i.e. a conjunction of simple CCRs. -Let 0}, be an e~pression of form n containing \[I\] I wish to thank Gerald Gazdar, Christa Hauenschild, William Keller, Daniel Maxwell, Manfred Pinkal, and Hans Uszkoreit for their comments on earlier versions of this paper. This work was carried out under the financial support of the BMFT of the German Federal Government. \[2\] Interpretations of R(~, t) and D(a, t) in terms of the theory of feature instantiation in GKPS would be 'the root of local tree t is an extension of ~' and 'some daughter in local tree t is an extension of ~'.</Paragraph> <Paragraph position="8"> only the predicate D; then simple CCRs \[3\] have the following forms: (4) Vt: R(~, t) \] (0' iff a I\[c0\]l Vt: 00' :\] R(~, t) iff Iko\]l Vt: C/0' iff I\[0)\]1 iff ~ I\[.--~W\]l Quantification is ignored in the notation on the right; ~ replaces P(a, t) and ~P(~, t) and ~-~ replaces ~P(a, t) giving 0o from (0', where P = R or D. The special brackets ' I\[ \]1 ' enclose daughters and render the indication of material implication superfluous. Using this notation, (2) and (3) may be restated as (5) mid (6), respectively: (5) S }\[ A \]l (6) I\[ C~D \]l To reformulate a set of ID rules we thus need (a) the definition of a set of branches constituting mother-daughter pairs and (b) an appropriate set of CURs. The definition of branches is permissive in the sense in which ID rules are permissive (cf GKPS, p. 76): branches with a conmmn mother can be adjoined to form a local tree. CCRs, like the LP rules, which also apply to local trees, are restrictive and limit the class of local trees admitted by the grammar. \[4\] How sets of ID rules may be reformulated in this manner will be illustrated in the following section.</Paragraph> </Section> <Section position="2" start_page="50" end_page="51" type="sub_section"> <SectionTitle> 1.2 Examples of CCRs </SectionTitle> <Paragraph position="0"> GKPS (pp. 47-49) exm, ines sets of simple context free rules and then proposes strongly equivalent descriptions in ID/LP format. One set of ID rules resulting from this reformulation is given in (7): Since none of the local trees admitted by (7) has more than one occurrence of a given category as daughter, we may say that the gran~ar first admits any strictly linearly ordered set \[5\] of branches \[3\] If categories are assumed to be atomic (e.g. S, NP, V) rather than complex for the moment, then it is unnecessary to mention more than one root category in a given CCR, \[4\] Note that the distinction of permissive vs. restrictive statements is closely related to that of inherited vs. instontioted feature specifications in the feature instantiation principles of GPSG. The theory would appear to gain in simplicity if a way could be found to eliminate these distinctions.</Paragraph> <Paragraph position="1"> \[5\] In order to simplify the present exposition, that share a conmmn mother as a local tree. This set of local trees must then be filtered with appropriate CURs so as to characterize the same set of local trees admitted by (7).</Paragraph> <Paragraph position="2"> A single CCR covers the trees with S as root: (9) CCR 1: S \]\[ NP ^ VP \]l CUR 1 states that NP and VP are obligatory in any local tree with S as its root. Since <S, AUX> is also a branch, MIX may optionally occur as daughter in such a tree.</Paragraph> <Paragraph position="3"> To characterize the local trees with VP as root we first construct the following function table:</Paragraph> <Paragraph position="5"> A &quot;l&quot; under a category (,n the right side of the table indicates that the category is a daughter in a given local tree; &quot;0&quot; means it is absent. If a local tree with the root on the left side of the table and the daughters marked &quot;1&quot; in a given line is to be admitted by the grarmuar, then a &quot;1&quot; appears under the root category in the corresponding line; &quot;0&quot; indicates that the tree is not admitted.</Paragraph> <Paragraph position="6"> A corresponding CCR of the form VP I\[('~\]\] can now be formulated, where (0 is a Boolean expression in conjunctive normal form. The terms of co are constructed from the lines designating inadmissible trees as follows: (II) ~(AUX A V) iff (~AUX v ~V) lines I, 2, 5, 6 ~(AUX A ~V A NP) iff (~AIJX v V v ~NP) 3 & 7 ~(AUX A ~VP) iff ('~AIIX v VP) 5 - 8 ~(~AUX A ~V) iff (AUX v V) II, 12, 15, 16 ~(~VP A V A ~NP) iff (VP v ~V v NP) \]4 & 16 The normalized terms of (Ii) are conjoined in the CUR of (12), which is reformulated with conditionals in (13) and then simplified in (14)'.</Paragraph> <Paragraph position="7"> (12) VP I\[(~AIIX v NV)^ (,-AUXv Vv ~NP) A (~AUR v VP) a (AUX v V) ^ (VP v~ V v NP)\]\] (13) VP \[\[(AUX D~V) A (hUX ~ (V v~NP)) ^ (AUX DVP) A(AUX vV) A (V ~(VPvNP))\]\[ (14) VP \[\[(AUR e~V)A (AUXD(VPA~NP))A (V~ (VPv NP))\]I local trees are assumed to contain than multisets of daughters.</Paragraph> <Paragraph position="8"> sets rather Next, (14) is reformulated as the three OORs of (15), which taken together with (8) and (9) admit the same set of local trees as the ID rules of (7):</Paragraph> <Paragraph position="10"> The CCRs of (15) have been formulated only on the basis of VP trees, however, and therefore fail to capture generalizations that apply to all local trees. In particular, any local tree with AUX as daughter - regardless of its root - must have a VP as sister, so CCR 3 may be restated as two simpler CCRs, CCR 2' and CCR 4', where CCR 2' does not depend on the root category. Furthermore, CCR 4 can be rewritten as CCR 5' since V cannot be a daughter of S. The following final set of CCRs thus emerges: (16) COR I': S \]\[ NP A VP \]\] CCR 2': \]\[ AUX ~ VP \]\[ CCR 3': VP \]\[ AUX e ~Y \]\] CCR 4': VP l\[ AUx D,--NP \]l CCR 5': \]\[ V m (VP v NP) \]\] It may first appear that the description with CCRs in (8) and (16) constitutes no clear gain over the ID rules of (7). The latter, however, are highly redundant and express none of the generalizations achieved in (16). Furthermore, the replacement of ID rules with CCRs is the essential prerequisite for the elimination of metarules described in section 2.</Paragraph> </Section> </Section> <Section position="3" start_page="51" end_page="52" type="metho"> <SectionTitle> \].3 The Complement-Type Principle </SectionTitle> <Paragraph position="0"> The ~ttempt to replace all ID rules with individual CCRs would lead to very complicated descriptions. Fortunately, the idea of CCRs can be utilized in a general principle that replaces all .lexJca\] ID rules (i.e. those which have a head that is an extension of a SUBCAT category; cf GKPS, p.</Paragraph> <Paragraph position="1"> 54), so that only nonleA'ical ID rules need be explicitly reformulated with individual CCRs.</Paragraph> <Paragraph position="2"> Shieber (1983) and Pollard (1985) have proposed that a list- or stack-valued feature (SYNCAT or SUBCAT) be introduced whose value contains the complements of a head category. This paper uses TYP as a syntactic feature with a semantically oriented and lexJcally determined semantic type as its value.</Paragraph> <Paragraph position="3"> Following the convention of GKPS (p. 189), '<~, B>' will be written for <TYP(~), TYP(~)> where ~ and are categories. Given the structure of complex types in GKPS as single-valued functions, the types may be viewed as lists or stacks.</Paragraph> <Paragraph position="4"> A Complement-Type Principle (CTP) can now be stated which has the form of a schematic CCR with conditions on variables: (\]7) (a)\]IX\[BAR 0, +H, TYP <6 I, <...<Sn_ l, 5n>...>>\] \]1 X\[TYP 5n\] (b) \[IX\[BAR 0, +H, TYP <61, <...<6n_l, 6n>...>> \] X\[TYP 51\] ^... ^X\[TYP 5n_l\]^ ~X\[TYP 6'\] \]I where (i) 5' ~ {61 ..... 5n_ l} ; (it) the mother X\[TYP 6n\] and head daughter X\[BAR 0, +HI are both ~\[CONJ\] ; \[6\] (iii) (a) and (b) are simultaneously fulfilled for a given assignment of types to 51, .... 5n_l, 6 n for 1 < n.</Paragraph> <Paragraph position="5"> CTP allows the complements of a head category to be read off from its semantic type if its mother is known. According to CTP the lexical head category V\[SUBCAT 46\] with type <VP\[-AUX, BSE\], <NP, S>> for the verb do has complement sisters VP\[-AUX, BSE\] and NP if its mother is S but has just the complement VP\[-AUX, BSE\] if its mother is VP, which has the type <NP, S>. The use of CTP in dealing with metarules will be shown in section 2 below, but first another general aspect of the metarule problem must be discussed.</Paragraph> <Section position="1" start_page="51" end_page="52" type="sub_section"> <SectionTitle> 1.4 Metaru\]es and Lexical Rules </SectionTitle> <Paragraph position="0"> GKPS introduces not only metarules, e.g. the Passive Metarule (p. 59) and the Extraposition Metarule (p. 118), but also related lexical rules involving the same phenomena, e.g. the Lexieal Rule for Passive Forms (p. 219) and the Lexical Rule for Extraposition Verbs (p. 222). The lexJeal rules are not fully formalized but all state roughly that if a given lexeme has a certain category, translation, and semantic type, then a particular form of the lexeme has a corresponding category, translation, and type.</Paragraph> <Paragraph position="1"> Since lexieal rules do most of the work, and given that metarules apply only to Je_vSeaJ ID rules, it is unclear why both should be needed for what is essentially one job. \[7\] CTP in fact allows the reduction of both devices, metarules and lexical rules, to one, here termed 'metalexical' (ML) rules. The latter are schematic rules of the form s =& ~, where a and 8 are category schemata which may contain variables in feature values. Ignoring the semantic translations of lexemes for the present, a ML rule states that if the lexicon conPSains an entry assigning ~ to lexeme w, then it also contains an entry assigning ~ to w; morphological rules determine the particular word form of w on the basis of syntactic features in the category. ML rules thus provide for an inductive definition of the lexicon. They handle not only phenomena like passive and extraposJtion but also, e.g. the subcategorization of sdng with or without an indirect object:, transitive or intransitive, etc.</Paragraph> <Paragraph position="2"> Examples follow in section 2, but next the entire formalism should be briefly summarized.</Paragraph> <Paragraph position="3"> \[6\] The restriction that both categories be ~\[CONJ\] (i.e. unspecified for CONJ) is necessary for coordination. In the structural analysis of bought and read books NP is the complement of the V dominating bought and read but not of the V dominating read.</Paragraph> <Paragraph position="4"> \[7\] Uszkoreit (1984, p. 65) has already expressed a similar view.</Paragraph> </Section> <Section position="2" start_page="52" end_page="52" type="sub_section"> <SectionTitle> 1.5 Sunmlary of the Formalism </SectionTitle> <Paragraph position="0"> The syntactic formalism proposed here proceeds by describing items (feature names and values, feature specifications, categories, and trees) with statements restricting the distribution of lower-level items within next-higher-level items. Feature nantes and atomic values are primitives. Complex feature values are categories or semantic types. A feature specification is an ordered pair <f, v> containing a feature nmne f and value v, where the latter is restricted by the feature-value rmlge of the former, h category is a set of feature specifications such that no feature name is assigned more than one value; it is legal iff it fulfills all Feature Cooccurrence Restrictions. h local tree is an ordered pair consisting of a legal root category and a list of legal daughter categories such that (a) the Complmnent-Type Principle, (b) tile Category Cooecurrence Restrictions, and (c) tile Feature Instmltiation Principles (i.e., respectively, lexical, nonlexical, and universal statements in the form of CCRs) as well as tile Linear Precedence statements are fulfilled. \[8\] A tree is an ordered pair consisting of a legal root category and a list of daughters, where each dau~,ter is either a tree or a word form. Word forms and their lexieal categories are specified by tile lexicon, defined by a list of basic lexical entries and metalexical rules.</Paragraph> <Paragraph position="1"> The gramlmar defines two binary relations over categories, ID and LP (the latter constitutiag the Linear Precedence statements). A binary relation R ~ is the extensional closure of R iff for each <~, g> in R, R ~ toni:sins every <y, 6> such that y and 6 are extensions (oF GKPS, p. 27) of ~ and 6, respectively.</Paragraph> <Paragraph position="2"> A local tree with root C and daughters C~, ..., C * . .o ~ n must fulfill him condltlons that <C , C.~ E ID= for 1 < i < n and <C., C.> ~ LP E+ (i.e? t~e transitive %- 1 . extensional elo~ure of LP) where 1 < 1 < n-1 and j = i+l.</Paragraph> <Paragraph position="3"> The proposed formalism utilizes more restricted memm tilmt GPSG but offers greater possibilities for expressing generalizations. The el iminat :ion of metarules and the introduction of CCRs give it a taore Ii~uogeneous struct:are and place cooccurrence restrictions of various kinds in the center of attention.</Paragraph> <Paragraph position="4"> For the present it may be best to regard this formalism as a particular variant of GPSG since most of tile central notions of the latter are retained.</Paragraph> <Paragraph position="5"> All that is sought is a simplification of GPSG as described in GKPS. Given the ricll palette of formal.tams recently proposed for kinds of unification gra~mlar~ it seems rather ingenuous to create a new name for thin modification of GPSG, as though tile multitude of remaining open questions were thereby answered. What we need is a metaformalism that will relate the insights of all the current formalisms through formal invariants preserved under translation from one formalism to another, and that will then truly deserve a name of its own.</Paragraph> <Paragraph position="6"> \[8\] The assmnption here is that any work done by tile Feature Specification Defaults (FSDs) of GKPS can be accomplished with suitably defined FCRs and CC~s. This will he illustrated in section 2 hut cannot be shown in general in this paper.</Paragraph> </Section> </Section> <Section position="4" start_page="52" end_page="53" type="metho"> <SectionTitle> 2. The Elimination of Metarules </SectionTitle> <Paragraph position="0"/> <Section position="1" start_page="52" end_page="53" type="sub_section"> <SectionTitle> 2.1 General Remarks </SectionTitle> <Paragraph position="0"> GKPS allows metarules to be used in ways that intuitively seem undesirable. For example, a metarule may simply indicate that. a daughter h of S is optional : (lS) ( s -> w, h ) -~ ( s--~ w ) The metarule is superfluous if A is enclesed in parentheses in tile corresponding ID rules: Single optional elements in the RHS of ID rules are permitted but have no theoretical status. Here the generalization is lost, however, that A is optional in all expansions of S.</Paragraph> <Paragraph position="1"> The Complement ~,ission Metarule proposed in GKPS (p. 124) is similar: (20) \[+N, BAR 1\] --b H, W \[+N, BAR 1\] .e H This metarule can be avoided \[9\] by simply adding tile target of the metarule to the set of base TD rules: (21) \[,N, Bhl~ 1\] ~ H But the formalism of GKPS does not permit more than one clement, to be enclosed in parentheses, so the following cannot he an II) rule: (22) S -~ A, (B, C) Aside from the use of parentheses to indicate single optional elements, none of tile ahhreviatory conventions proposed in Chomsky/Hal \]e ( 1968, pp. 393-399) are enlployed in GPS(\]. Thus, the rules of Since such abbreviatory conventions for expressing coocurrence restrictions are not provided by GPSG, it. is not ~.mrprising that timir work is assumed by metarules. GEPS in fact ,!~tates that metarules &quot;amount to notifing more than a novel type of rule-collapsing convention for rules&quot; (p. 66).</Paragraph> <Paragraph position="2"> Now that CCRs have been presented above in section 1.2 for restating a simple GPSG tllat does not contain metarules, we Call examine |low they may be used tO e\]inlinate metarules fram the GPSG proposed for English in GKPS.</Paragraph> <Paragraph position="3"> \[9\] Note that tile metarule does not provide for the omission of a sJnK.le complement from a Kraal ol&quot; money to tile linffuists or gratefu\] to the ;ttJnJstrV /br ~he money.</Paragraph> </Section> <Section position="2" start_page="53" end_page="53" type="sub_section"> <SectionTitle> 2.2 The Passive Metarule </SectionTitle> <Paragraph position="0"> GKP8 (p. 59) presents a Passive Metarule (PM) of remarkable simplicity and generality:</Paragraph> <Paragraph position="2"> PM states that for every lexical ID rule expanding VP and containing NP and any multiset W of categories in the RHS, there is a corresponding lexical ID rule expanding VP\[PAS\] and optionally containing PP\[by\] in place of NP in its RHS. Although the head V dominated by VP\[PAS\] is not mentioned in PM, it must be specified <VFOEN~ PAS> in a local tree by virtue of the Head Feature Convention.</Paragraph> <Paragraph position="3"> As noted in section 1.4, however, PM does only a small part of the work for passive, the main task &quot;falling to the Lexical Rule for Passive Forms.</Paragraph> <Paragraph position="4"> Moreover, some of the predictions of PM are incorrect. Thus, PM applies to the lexical ID rule introducing V\[SUBCAT 20\], to which bother belongs: (25) VP\[AGR S\] --> HI20\], NP But the derived ID rule for V\[20, PAS\] incorrectly allows a PP\[PFORM by\] complement. \[10\] Furthermore, sentences like That Santa Claus exists .is believed by Kim. are grammatical, but PM does not: apply to the lexical ID rule introducing V\[SUBCAT 40\] for complements 6 , .... 6 , while V\[+PAS\] nith mother VP (of type <~ ,, S>) hnsleomplements 6 ..... , 6 n- t , l n-z and, opt*onally, 6 n.</Paragraph> <Paragraph position="5"> \[I0\] V\[PAS\] is specified <SUBCAT, 2> in ,h~n was bothered ~Y his boss.</Paragraph> </Section> <Section position="3" start_page="53" end_page="53" type="sub_section"> <SectionTitle> 2.3 The 'Subject-Aux Inversion' (SAI) Metarule </SectionTitle> <Paragraph position="0"> The second metarule for English discussed in GEPS is the 'Subjeet-Aux Inversion' (SAI) Metarule (pp. 60-65): (28) V2\[-SUBJ\] &quot;--> W V2\[+INV, +SUBJ\] --~ W, NP This applies to all lexical ID rules expanding VP. \[II\] Because of (29), however, local trees are admitted only by derived IB rules produced by its application to base lexical ID rules expanding categories specified VP\[+AUX\]: (29) \[+INV\] = \[+AUX, FIN\] (FCR 1) Most of the work of this metaru\]e can be taken care of simply by the CTP since a lexical head Y with the type <6 I, <...<6n, <hiP, S>>...>> has the complements 61, ..., 6 if its mother is VP (of type <NP, S>) and {he complements &l' '''' 6n, NP if the mother is S. Further restrictions must determine when V has which mother. In addition to the FCRs of (29) and (30), retained from GKPS, the new FCR of (31) is introduced: (30) \[+INV, BAR 2\] D \[+SUBJ\] (FCR I0) (31) \[INV\] ~ \[+V, -N\] INV is a HEAD feature subject to the Head Feature Convention (cf GKPS, pp. 94-99), so a V 2 mother of V\[+INVJ must be specified <INV, +> and therefore also <SUBJ, +>. If V is specified <INV, -> (note that (31) requires it to have some specification for INV), then its mother is *lot an extension of V 2 (providing for coordination) or it is specified <SUBJ, -> according to the following CCR: (32) I\[ V\[-INV\] 31 (~V 2 v \[-SUBJ\]) \[12\] Although GKPS provides for ,an embedded inverted sentence in What dJd you see? , no embedded nonhead Recall the use of aliases in GKPS (p. 61) whereby 'VP' stands for V2\[-SUBJ\] and 'S' for V2\[+SUBJ\].</Paragraph> <Paragraph position="1"> Note that this CCR contains a disjunction of root descriptions and thus does not conform to the schemata for simple CCRs with atomic categories presented in section 1.1 above. The disjunction is to he read &quot;the root is not an extension of V 2 or it is an extension of It applies to any \]exical ID rule with a category specified <tIAR, 2> in the RItS and produces a rule with the specification <NULL, +> added to this category.</Paragraph> <Paragraph position="2"> It turns out that S'1%1\] lnay be eliminated with two simple statements. An FCR expresses the fact that a category is ~pecified for NUI,L (i.e. NULL takes the value + or -) if and only if it also is <BAR, 2>: (39) \[NULLI -= \[BAR 2\] A CCR then stipulates that a category specified <NULL, +> mu'4t have a lexical category as its sister in a local tree: .(40) It \[+NULL\] m \[BAR 0\] \]1 This is equivalent to the condition that STN1 - like all metarule:~ - may only apply to lexical IB rules. Note that a root category is not indicated in (40) and that parasitic gaps (of GKPS, pp. 162 if) are provided for.</Paragraph> <Paragraph position="3"> As in GKPS, an FCR requires that a category specified <NUI,L, +> also be specified for SLASH: (41) \[+NULL\] ~ \[SLASH\] (FCR 19) The distribution of SI,AStI is in turn governed by the CAP, HFC, and FFP. GKPS also postulates an FSD for NULl, : (42) ~\[NULL\] (FSD 3) FgD 3 is not required in tills analysis since categories specified <BAR, 2> are freely specified with values from (4, -} for NULl,, while all other categories must he unspecified for NULL according to (39).</Paragraph> <Paragraph position="4"> The treatment of gaps in GKPS is completed with the Slash Termination Metarule 2 (STM2) (cf GKPS, pp.</Paragraph> <Paragraph position="6"> S~'M2 says that for every \]exical ID rule introducing V ~ \[+SUB J, FIN\] as a daughter, there is a corresponding rule with V2\[-SUBJ, FIN\] in place of V 2\[~SUBJ, FIN\] and with the mother specified <SLASI{, NP>.</Paragraph> <Paragraph position="7"> Examination of the lexical \]D rules proposed for English in GKI)S reveals that all @\[FIN\] daughters introduced are also specified <SUB J, +>. We may therefore reformulate tim types of the \]exical head cat.egories so that V 2\[FIN\] complements do not carry the specification <SUBJ, +>. The feature SUBJ is then freely specified but restricted by the FCR in (44) and the CCR in (45): (44) \[SUBJ\] r~ \[-~V, -N, lIAR 2\] (/15) 1\[ \[BAR 0\] ^ V 2 \[-SI, JI'IJ, FIN\] \]1 X/NP The CCR of (4.5) states that a local tree with V2\[-SUBJ, FIN\] and \[BAit O\] as daughters must have a root specified <SLASII, NP>. As :in the case of STM\], the stipulation of a \[BAR O\] sister is the CCR counterpart of the requirement that metaru\]es apply only PSo lexical IB rules.</Paragraph> <Paragraph position="8"> Taken together, the two FCRs of (39) and (44) plus the two CCRs of (40) and (45) accomplish all the work of STM1 and STM2 and result in the same analyses for English as adopted in GKPS.</Paragraph> </Section> </Section> class="xml-element"></Paper>