| { | |
| "paper_id": "C88-1049", | |
| "header": { | |
| "generated_with": "S2ORC 1.0.0", | |
| "date_generated": "2023-01-19T12:15:56.639201Z" | |
| }, | |
| "title": "CHART PARSING ACCORDING TO THE SLOT AND FILLER PRINCIPLE", | |
| "authors": [ | |
| { | |
| "first": "Peter", | |
| "middle": [], | |
| "last": "Hellwig", | |
| "suffix": "", | |
| "affiliation": { | |
| "laboratory": "", | |
| "institution": "University of Heidelberg", | |
| "location": { | |
| "postBox": "P.O. Box 105 760", | |
| "postCode": "D-6900", | |
| "settlement": "Heidelberg", | |
| "region": "FRG" | |
| } | |
| }, | |
| "email": "" | |
| } | |
| ], | |
| "year": "", | |
| "venue": null, | |
| "identifiers": {}, | |
| "abstract": "", | |
| "pdf_parse": { | |
| "paper_id": "C88-1049", | |
| "_pdf_hash": "", | |
| "abstract": [], | |
| "body_text": [ | |
| { | |
| "text": "is an algorithm that assigns a structural description to a string according to a grammar. It follows from this definition that there are three general issues in parser design: the structure to be assigned, the type of grammar, the recognition algo~ rithm. ", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "A parser", | |
| "sec_num": null | |
| }, | |
| { | |
| "text": "The structuring principle of constituency trees is concatenation and the part-whole -relationship. The structuring principle of dependency trees is the relationship between lexemes and their complements. Note: It is not correct (or at least misleading) to define dependency as a relationship between words, as it is often done. The possibility and necessity of complements depend on the lexical meaning of words, i.e. a word which denotes a relationship asks for entities which it relates, a word which denotes a modification asks for an entity which it modifies etc.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Dependency Structure", | |
| "sec_num": "1." | |
| }, | |
| { | |
| "text": "While it is awkward to associate functions (deep cases, roles, grammatical relationships) with phrase structures, it is not difficult to paraphrase the functions of complements on a lexical basis. For example, the argument of the predicate \"sleep\" denotes the sleeper; the meaning of \"persuade\" includes the persuader, the persuaded person and the contents of the persuasion. In a next step, one can abstract from the concrete function of dependents and arrive at abstract functions like subject, object, adjunct etc.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Dependency Structure", | |
| "sec_num": "1." | |
| }, | |
| { | |
| "text": "Of course, the complements covering these roles can be single words as well as large phrases; for example \"John\", \"my father\", \"the president of the United States\" can all fill the role of the sleeper with respect to the predicate \"sleep\". However, phrases need not be represented by separate nodes in dependency trees (as they do in phrase markers) because their internal structure is again a question of dependency between lexemes and their complements. be handeled completely in parallel, as opposed to the two-phase mechanism which, for example, characterizes Lexical Functional Grammar.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Dependency Structure", | |
| "sec_num": "1." | |
| }, | |
| { | |
| "text": "Each element in the dependency tree carries three labels: a role (which applies to the (sub)tree of which the element is the head), a lexeme, and a set of grammatical features. It is widely accepted that chart parsing is superior to backtracking or to parallel processing of every path. A common version of a chart can be vizualized as a network of vertices representing points in the input, linked by edges representing segments. The edges are labelled with the categories that the parser has assigned to the constituents concerned.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Dependency Structure", | |
| "sec_num": "1." | |
| }, | |
| { | |
| "text": "Alternatively, each edge is associated with a complete structural descrLption, including the information which is carried by the covered edges. In this case, a chart is simply a collect]on of trees (implemented as lists) projected on the various segments in the input. The innovation with regard to chart parsing th~vt is proposed in this paper is a label.ling of edges by trees that comprise slots.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Dependency Structure", | |
| "sec_num": "1." | |
| }, | |
| { | |
| "text": "beginning, an edge for each word is entered into the chart. Each edge is label] o~ ed with a tree. The head of this tree contains the lexeme that is associated with the word according to the ].exicon; it carries a morpho-syntactic category according to the morphological properties of the word in question: it normally contains a variab].e as a role l~arker, since the syntagmatic function of the corresponding segment is still unknown. A slot is subordinated to the head for each element that is to be dependent in the resulting structure, if any. Slots are added to a lexical item according to c~>mpletion patterns refered to in the lexicon. (We can not qo into details here.) Subsequently, each tree in the chart looks for a slot in a \"tree that is associated with annother edge.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "At the", | |
| "sec_num": null | |
| }, | |
| { | |
| "text": "If the head of the searching tree fitn the description in the slot then a new edge is drawn and labelled with the compound tree that results from inserting the first tree into the second. The categories of the ~ew tree are the result of unifying the categories of the slot tree and the filler tree.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "At the", | |
| "sec_num": null | |
| }, | |
| { | |
| "text": "Special features state the positional re~/irements, e.g. whether the segment corresponding to the filler has to preceed or to follow of the segment corresponding to the element dominating the slot. This process continues until no new tree is produced. Parsing was successful if at ].east one edge covers the whole input. The dependency tr~e associated with this edge is the desired structural description. ", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "At the", | |
| "sec_num": null | |
| }, | |
| { | |
| "text": "In figure 2, the vertices represent left and right margins of segments. Adjacency is the inherent positional relationship in this model.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "A chart for discontinuous segments", | |
| "sec_num": "3." | |
| }, | |
| { | |
| "text": "As a consequence, this chart does not allow for discontinuous constituents. This is a serious deficiency considering the phenomena of unbound dependencies which occur in many languages. The representation of position by categoriesj however, opens up the possibility to state various kinds of positional relationships between heads and dependents. In order to form discontinuous segments, the control of positions in the chart must be altered. The solution which we adopt is to represent the extensions of seg-ments by bit strings consisting of one bit", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "A chart for discontinuous segments", | |
| "sec_num": "3." | |
| } | |
| ], | |
| "back_matter": [], | |
| "bib_entries": {}, | |
| "ref_entries": { | |
| "FIGREF0": { | |
| "num": null, | |
| "text": "Flyir,g planes can be dangerous.The lexicon lookup leads to the initialization of %he chart in figure i.", | |
| "type_str": "figure", | |
| "uris": null | |
| }, | |
| "TABREF2": { | |
| "text": "The only mechanism needed for draw-ing up complex structures is the unification of slots and potential fillers.", | |
| "type_str": "table", | |
| "content": "<table><tr><td colspan=\"2\">the lexeme</td><td colspan=\"6\">position, and with a categoriza-</td></tr><tr><td colspan=\"8\">tion that covers all of the morpho-syntactic</td></tr><tr><td colspan=\"3\">properties of</td><td colspan=\"4\">the appertaining</td><td>complement.</td></tr><tr><td>If cross</td><td colspan=\"5\">categorization does</td><td/><td>not allow all</td></tr><tr><td>of the</td><td colspan=\"5\">p~ssible properties</td><td colspan=\"2\">of a complement</td></tr><tr><td colspan=\"8\">within one category to be stated, a disjunc-</td></tr><tr><td>tion of</td><td colspan=\"7\">slots is used to express the alter-</td></tr><tr><td colspan=\"2\">natives. The control</td><td/><td>of</td><td>the</td><td colspan=\"2\">parsing</td><td>process</td><td>is</td></tr><tr><td colspan=\"8\">achieved by means of a well-formed substring</td></tr><tr><td colspan=\"3\">table ((]hart).</td><td/><td/><td/><td/></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>Constituency and</td><td>dependency both have to be</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>represented somehow</td><td>or other in the syntac-</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>tic description.</td><td>As a consequence,</td><td>recent</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>developments have</td><td>led to</td><td>a convergence</td><td>of</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>formalisms of both origins</td><td>with respect to</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>their contents. (A good example is the simi-</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>larity between</td><td>Head-Driven Phrase Structure</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>Grammar /Pollard,</td><td>Sag 1987/</td><td>and Dependency</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>Unification</td><td>Grammar</td><td>/Hellwig</td><td>1986/.)</td><td>If</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>phrase structure trees are used, the differ-</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>ence between</td><td>governor and dependent must be</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>denoted by</td><td>the categories</td><td>that</td><td>label</td><td>the</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>nodes, e.g.</td><td>by a x-bar notation. If depen-</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>dency</td><td>trees</td><td>are</td><td>used,</td><td>the</td><td>concatenation</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>relationship must</td><td>be denoted</td><td>by positional</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>features</td><td>which</td><td>are</td><td>part</td><td>of</td><td>the</td><td>complex</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>morpho-svntactic category.</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>2. Chart parsing based on a lexicalized</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>grammar</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>The structure</td><td>to be associated with a well-</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>formed string</td><td>can be</td><td>defined in</td><td>two ways:</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>either by</td><td>a set</td><td>of</td><td>abstract</td><td>rules</td><td>which</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>describe the</td><td>possible constructions</td><td>of the</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>~language or by a description of the combi-.</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>nation capabilities</td><td>of the</td><td>basic elements.</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>The latter</td><td>fits</td><td>with</td><td>the</td><td>dependency</td><td>ap-</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>proach. Given a lexical item and its morpho-</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>syntactic properties,</td><td>it is relatively easy</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>to give</td><td>a precise description of its possi-</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>ble complements.</td><td>The main advantage of this</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>lexicalistic approach</td><td>is the fact that aug-</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>menting or</td><td>changing the</td><td>description of</td><td>an</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>item normally</td><td>does not</td><td>interfere with</td><td>the</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>rest while</td><td>any change in a rule-based gram-</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>mar might</td><td>produce unforeseen</td><td>side</td><td>effects</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>with regard to the whole.</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>The prerequisite for a lexicalized dependen-</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>cy grammar</td><td>are trees that comprise slots. A</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>slot is</td><td>a description of the head of a tree</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>that fits</td><td>into another</td><td>tree.</td><td>Formally,</td><td>a</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>slot is</td><td>a direct dependent of a head with a</td></tr><tr><td/><td/><td/><td/><td/><td/><td/><td>role associated</td><td>to it,</td><td>with a variable in</td></tr></table>", | |
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| "TABREF3": { | |
| "text": "The ch~Lrt at the end of tbe pnrsl:~g process", | |
| "type_str": "table", | |
| "content": "<table><tr><td>I%\u00b0,-</td><td/><td/><td/><td/><td/></tr><tr><td>noun re)</td><td/><td/><td/><td/><td/></tr><tr><td/><td>un---</td><td/><td colspan=\"2\">Ivu~b -f~n</td><td colspan=\"2\">IveTb inf</td><td>ladje)</td><td>lassert$on[</td></tr><tr><td/><td colspan=\"4\">(ATr{._ adje la)) I verb I (~v_</td><td colspan=\"2\">I (eA_ I ndje ra))l I</td><td>I--~I I verb</td><td>I</td></tr><tr><td/><td/><td/><td colspan=\"3\">l~f ~~) I</td><td>i</td><td>I fin ~a))[</td></tr><tr><td>Flying</td><td colspan=\"2\">planes</td><td/><td>can</td><td/><td>be</td><td>dangerous</td></tr><tr><td colspan=\"7\">Fig. 1 The chart at the end of the lexicon phase</td></tr><tr><td colspan=\"2\">(The notation</td><td/><td>is</td><td colspan=\"3\">simplified</td><td>and</td><td>we</td><td>have</td></tr><tr><td colspan=\"7\">omitted a detailed categorization.</td><td>The de-</td></tr><tr><td colspan=\"4\">pendency structure</td><td>is</td><td colspan=\"2\">represented</td><td>by</td><td>the</td></tr><tr><td colspan=\"4\">bracketing. Lexemes</td><td colspan=\"2\">are</td><td>underlined;</td><td>roles</td></tr><tr><td>are in</td><td colspan=\"6\">capita] letters; slots are marked by</td></tr><tr><td colspan=\"3\">the underscore</td><td colspan=\"4\">in the lexeme position. \"re\"</td></tr><tr><td colspan=\"2\">means right</td><td colspan=\"5\">adjacent, \"la\" means left adja-</td></tr><tr><td colspan=\"7\">cent with respect to the head. )</td></tr><tr><td>/</td><td/><td/><td colspan=\"2\">I (suBJ _.</td><td/><td>/</td><td>I</td><td>i</td></tr><tr><td>Flying</td><td colspan=\"2\">planes</td><td/><td>can</td><td/><td>be</td><td>dangerous</td></tr><tr><td>Fig. 2</td><td/><td/><td/><td/><td/></tr></table>", | |
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