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<?xml version="1.0" standalone="yes"?> <Paper uid="P85-1003"> <Title>EIR.S E,R.S S,R.E S, RoE S~R.E S~RoE PAST PERFECT E~SoR SIMPLE PAST E.SoR PRESENT PERFECT EoS,R SIMPLE PRESENT E.S,R SIMPLE PRESENT SIEoR SIMPLE FUTURE SoE. R S, EmR S.E.R RoSoE Ro$.E R~E~S R~E,S</Title> <Section position="4" start_page="18" end_page="19" type="metho"> <SectionTitle> 1. SIMPLE PAST E,R_S 2. PAST PERFECT E_.R_S 3. SIMPLE PRESENT S,R,E 4. PRESENT PERFECT E_S.R 5. SIMPLE FUTURE S_R,E 6. FUTURE PERFECT S_E~R </SectionTitle> <Paragraph position="0"> The notation here demands some explanation. The underscore symbol &quot;~&quot; is interpreted as the &quot;less-than&quot; relation among time points whereas the comma symbol .... stands for the &quot;teas-than-or-eQual-to&quot; relatmn. As an illustration, the present perfect tense denotes a situation in winch the moment of speech is either cotemporaneous or precedes the reference point, while the moment of event =s strictly before the other two moments.</Paragraph> <Paragraph position="1"> Note that Hornstem also uses the term &quot;assoc=ation&quot; to refer to the comma symbol &quot;,&quot;.</Paragraph> <Paragraph position="2"> Geven the bas=c tense structure for a s=mole tensed sentence, the mterpretat=on of the sentence that arises from the interact=on of tense and time adverbs ~s represented by the modihcatmn of the posit=on of the R or E points to form a new tense structure wh=Ch we call a aermeO lense structu,e. In two papers (Hornstem77 & Hornstem81), Hornstem proposes three formal constraints that hmlt the class of derived tense structures that can be generated from the bas=c tense structures m SuCh a way as to capture the acceptabd=ty of sentences containing temporal adverbs (e.g.. now, yesterday, tomorrow), temporal connechves (e.g., when. before, after), and md=rect speech. In the rest of tins sect=on, I shall examine the adeouacy of these constraints.</Paragraph> <Paragraph position="3"> (1) The linear order of a clenved tense structure must be the same as the hnear order of the basic structure.</Paragraph> <Paragraph position="4"> (2) NO new assoc=at=on ~s ;roduced =n the clerfved tense structure. LOG IS st=oulated to account for examoles cons=st=ng Of a single temporal adverb such as (4a) and those w~th two hme adverbs such as ~'32). 2 4a. Jonn came home i. &quot;now, at this very moment i. yesterOay iii. &quot;tomorrow 32 a. Jonn left a week ago \[from\] yesterclay.</Paragraph> <Paragraph position="5"> h. \[From\] Yestertlay, Jonn left a week ago.</Paragraph> <Paragraph position="6"> c. degA week ago. Jonn left \[from\] yesterday.</Paragraph> <Paragraph position="7"> The basic tense structure for 4(ai) is: E,RoS (sim\[ole past: Jonn came t~ome) NOw modifies E or R so that they become cotemporaneous with ll~e moment of speech S with the clerived tense structure as 1. Hornstem actua=ly ksNid tone ~a~lC/ ter~ Put I *.,gmk U~e Dn~otes3~ve Oo~onQs to tfle Dromnce of asoect fqltrtet flqn te~. 2. The ,num~nnOs are Homstlm~'s. follows: E,R,S (BAD: violates LOC since new association is produced) On the other hand, 4(aii) is acceptable because the modifier yeslerOay leaves the tense structure unchanged:</Paragraph> <Paragraph position="9"> The crucial example, however, ms 5(c): 3 5c. John has come home i. ?right now ii. &quot;tomorrow iii. yesterday.</Paragraph> <Paragraph position="10"> LOC predicts (wrongly) that 5cii is good and 5ciii bad. 4 But LOC gives the wrong prediction only on the assumotmon that the basic tense structures are correct. To account for 5c. i propose to save the LOC and change the following SRE assocmatmon with the present perfect:</Paragraph> </Section> <Section position="5" start_page="19" end_page="21" type="metho"> <SectionTitle> PRESENT PERFECT E_R.S </SectionTitle> <Paragraph position="0"> With the modified basic tense structure for present perfect. LOC will give the correct analysmS. 5cii =s bad because:</Paragraph> <Paragraph position="2"> (OK: no new linear order and no new comma.) The questmon that naturally arises at this point ms: Why does Hornstein not choose my prooosed SRE structure for the present perfect? The answer, I befieve, will become apparent when we examine Hornste,n's Second constra, nt, The rule for temporal connectives (RTC) states that (p.539-40): For a sentence of the form Pl.conn-P 2 where &quot;conn&quot; ~s a temporal connectmve such as &quot;when&quot; &quot;before&quot;, &quot;after&quot; etc.. line up the S pomt~ of Pt and F 2, that IS. wnte the tense structure of Pl and P2' lining uP the S points. Move R 2 to under R 1, placing E 2 accorc=ngiy to preserve LOC on the bes=c tense structure. It can be easily seen that my proposed tense structure for present 3. See- toot;tote 7 ~ 11 Of Morn~Itein'$ ~IO~'.</Paragraph> <Paragraph position="3"> 4 There rely Oe clouOts ~ re0a~s II~ ac=~ta~ilily of 5dii. An ~uiY=1m~ t~ ot 5C/iii ~ aC/clmtal~ ,~ Dan~ (JeSl~lrJI4ll~. D.271\]. A~IO. in French, IRe I ~'e~t moment (Comne76, D.al).</Paragraph> <Paragraph position="4"> perfect does not work with RTC since it produces the wrong predictions for the following two sentences: \[1 \] &quot;John came when we have arrived.</Paragraph> <Paragraph position="5"> \[2\] John comes when we have arrived.</Paragraph> <Paragraph position="6"> For \[1\] the new analysis is:</Paragraph> <Paragraph position="8"> E~R. S EIR~S which does not violate the RTC and hence predicts (wrongly) that \[1 \] =s acceptable. Similarly, for \[2\], the new analys,s is: S.R,E -- S.R.E . (violates RTC) I I E~R. S EIS, R which prediCtS (wrongly) that \[2\] is bad. This may explain why Hornstem decides to use E_S,R for the present perfect because =t can account for {1 } and {2\] with no difficulty. However. I suggest that the correct move snould be to abandon RTC which has an asymmetrical property, I.e., it matters whether Pl or P2 =s put on top, and does not nave an obwous semanttc explanatmon. (See Hornstetn's footnote 20, p.54,.3). My second proooTw31 is then to replace RTC with a Rule of R.permanence (RP) stating that: (RP): Both the S and R points of Pl and P2 must be ahgned without any mamp-latmn of the tense structure for P2&quot; Thus sentence \[3l: {3\] .John came when we had arrivecl.</Paragraph> <Paragraph position="9"> ~s acceptable because its tense structure does not v=otate RP: E.R__S (OK: S and R points are EIRI$ already aligned) NOW, ~et us reconsider sentences \[1\] and \[2\]. Sentence \[1\] is not acceptable uncler RP and the new tense structure for present perfect since:</Paragraph> <Paragraph position="11"> Sentence \[2\] ,s still a problem. Here I snail maKe my third proposal, namely, that tne simple present admits Iwo Ioas~c tense structures: To examinethe adeouacy of RP. letuslook at more examples: \[4\] John has come when i. &quot;we arrived if. &quot;we had arrived iii. we arrive iv, we have arrived v. &quot;we will arrive The corresponding analysisisasfollows: We can see that the proposed theory correctly predicts all ol the five cases. There ts. however, an apparent counter.example to RP which, unlike RTC, is symmetncal, Le., it does not ma~ter which Of the Pi's =s put on the top. Cons=der the following two sentences: \[5\] i. John will come when we arrive.</Paragraph> <Paragraph position="12"> if. &quot;John arrives when we wi11 come.</Paragraph> <Paragraph position="13"> RP predicts both 5i and 5if will be unacceptable, but 5i seems to be good. It ts examples like 5i and 5if, I believe, that lead Hornstem to propose the asymmetrical rule RTC. But I think the data are m~slead=ng because =t seems to be an ,diosyncrasy of Enghsh grammar that 5i =s acceptable. In French, we have to say an ecluwatent of &quot;John will come when we wdl arrive&quot; with the temporal adverb=al expl=c~tly marked with the future tense (Jespersen6~, p.264). Thus. the acceptability of sentences like 5i can be explained Oy a !ormc=ple of Economy of Speech allowing us to om=t the future tense of the temporal adverbial if the matrix clause is already marked w~th the tuture tense.</Paragraph> <Paragraph position="14"> Now, we clescribe the third and final grammatical constraint on sequences of tense. Consider the following sentences: \[6\] John said a week ago that Mary (a) will leave in 3 days.</Paragraph> <Paragraph position="15"> {b) would In the (a) sentence, the temporal interpretatmn of the embedded sentence is evaluated w=th respect to the moment of speech. Thus. for instance, \[6a\] means that Mary's leaving is 3 days alter present moment of speech. On the other hand, the (b) sentence has the temporal intemretatlon of the embedded sentence evaluated with respect to the interpretation of the matrix clause, Le., \[6b\] means that Mary's leaving is 4 days before the moment of speech.</Paragraph> <Paragraph position="16"> To account for the sequence of tense in reported speeCh, Hornstein proposes the following rule: (SOT): For a sentence of the form &quot;P1 that P2&quot;' assign S 2 with</Paragraph> <Paragraph position="18"> In general, for an n.level embedded sentence, SOT states that: assign S n with En. 1 (Hornslem81, p.140). With the SOT rule, \[6a\] and \[6b\] will be analyzed as follows:</Paragraph> <Paragraph position="20"> The local property of SOT, Le., linking occurs only between nth and (n-1)th level, has a n~ce conseouence: ,t ex0tams wny a third level nested sentence like \[7\]: has only two temporal readings: (1) sn 7(ci). Mary's leaving is two days after the moment of speech, and (2) m 7(cii), Mary's leaving Js two clays Oetore the moment Of speech. In part=cular, there ~s not a temporal reading corresponding to the situatmon fn which Mary's leaving ms hve days before the moment of speech. We would obta,n the th=rd reading if SOT allowed non-local hnking, e.g., ass=gned S 3 with E 1 .</Paragraph> <Section position="1" start_page="20" end_page="21" type="sub_section"> <SectionTitle> 2.2 Explanations of the Formal Constraints </SectionTitle> <Paragraph position="0"> In the prewous section, we have examined three formal constraints on the denvatmn of complex tense structures from the Oas,c tense structures: (1) LOC. (2) RP, and (3) SOT. NOw, I want to show how the LOC falls out naturally from the computat=onal propertms of a temporal reasoning system along the line suggested by Allen (Allen84, Allen83), and also how the RP and SOT constraints have mtuitwe computat=onal motwation.</Paragraph> <Paragraph position="1"> The bes,s of Allen's comDutat=onal system ts a temporal logic based on intervals instead of time points. The temporal logic cons=stS of seven basic relations and their mveraes (Allen84, D.129, figure 1):</Paragraph> </Section> </Section> <Section position="6" start_page="21" end_page="23" type="metho"> <SectionTitle> YYYY </SectionTitle> <Paragraph position="0"> The reasoning scheme tsa form of constraint propagation in a network of event nodes hnKed by temporal relat,onsmps. For instance, the situat=on as clescribed in the sentence &quot;John arrived when we came&quot; is represented by the network: where A = John's arrival and B = Our coming This network means that both event A and event B are before now, the moment of speech, while A can be before, alter or s=multaneous with B.</Paragraph> <Paragraph position="1"> When new temporal relatlonsmos are added, the system maintains consistency among events by orooagat,ng the effects of the new relatmnsmos wa a TaO/e ol Translt~wty Re/at~onsmps that tells the system how to deduce the set of adm=ss=ble relat=onsmos between events A and C given the retatlonsh=ps between A and B, and between B and C. Thus, for instance, Irom the relationships &quot;A during B&quot; and &quot;B < C&quot;, the system can deduce &quot;A < C&quot;. One orooerty of the constraint propagation algorithm generally =s that further mlormatlon only causes removal of members from the set of admissible labels, i.e., teml=orat relatlonsmDs, between any two old events (Allen83, p.8,35). NO new label can De added to the admissible set once it is created. Let us call Ires property of the constraint propagntlon algor, tnm the Delete Labei Condit=on (DLC). DLC can be mteroreted as a k=nd of reformation monotonicity condition on the temocral representation.</Paragraph> <Paragraph position="2"> Let u5 further restrict Allen's temooral logic to instantaneous intervals. ~.e.. each event corresponds to a single moment of time. The restricted logic has only one or,mitwe relat,on, <, and three ctner denved relat,ons: <, >, and >. There is a straightforward :ranslat=on of Hornstein's SRE notation =nto the network re=)resenta'Jon, namely, replace each comma symbol &quot;,&quot; by < (or >. witr the event symbols reverse their roles) and each underscore symbol &quot;~&quot; by > (or < with similar aC/liustment on the event symbols). Thus, a tense structure such as: E_R,S can be represented as: We can see that each of these cases ~s a v=olatlon of the DLC. To spell this out. we have tt~e following operations on the constraint network corresponding tO the above vlolat=ons of the LOC:</Paragraph> <Paragraph position="4"> In each of these cases, the operation involves the addihon of new members to the adm=ss=Dle set. Th=s =s ruled out Ioy DLC. Thus, we have the result that if LOC =s wolated, then DLC =s v=olated. In other words. DLC -- LOC. 5 --I The second constraint :o be accounted for is the RP which effecbvely states that (a) the 50omts of the matrix clause and the temporal adverb=al must be ~clent=cal. and (b) the IR !0dints of the matrix clause and the temporal aOverbml must be ~dent=cal. One nypothests for th,s rule is that: (H1) Only the matrix clause mtrocluces distract S and R points.</Paragraph> <Paragraph position="5"> in other words, the non-subcate<Jonzable temporal adjuncts do net ado new S and R points.</Paragraph> <Paragraph position="6"> H1 has to be modifieO slightly to taV, e the case of embedded sentence =nto account, namely, {Revised RP): Only the matrix clause and the subcategorizable SCOMP or VCOMP can introduce d=stinct S and R points.</Paragraph> <Paragraph position="7"> where SCOMP and VCOMP stand for sentent=al complement and S. The C/om,e~e o~ thss Ihe~n ~' nm true.</Paragraph> <Paragraph position="8"> verbal complement respectively. The interesting point is that both the rewsed RP and the locality property of SOT can be easily implemented ,n processing systems which have certain Oounoeoness constraint on the phrase structure rules (e.g., ,nformation cannot move across more than one bounding node). To illustrate this. let us consider the following tense interpretation rules embedded in the phrase structure rules Of the</Paragraph> <Paragraph position="10"> The S rule introduces a new S point and sets its value to now, The VP rule has two effects: (I) it does not introduce new S or R points for the temooral adveriolal phrase, thus imohcltly incorporating the revised RP rule, and (2) it looks at the tense of the embedded sentential comolement, setting the value of its S point to that of the E point of the higher clause if the tense is past, and to now, otherwise. Thus. tn th~s way, the second effect accomplishes what the SOT rule demands.</Paragraph> <Section position="1" start_page="22" end_page="23" type="sub_section"> <SectionTitle> 2.3 Implications for Learning </SectionTitle> <Paragraph position="0"> If the revisions to Hornstem's theory Of tense are correct, the natural cluest=on to de asked is: FlOW dO speakers attain such Knowledge? This Question has two Darts: (1) How do spea~ers acquire the formal constraints on SRE derivation? and (2) How do speakers learn to associate the appropriate SRE structures with the baszC tenses of the language? Let us consider the first sub-Question. In the case of LOC, we have a neat answer .. the constraint need NOT be learned at all! We have shown that LOC falls out naturally as a consequence of the architecture and processing algorithm ot the computational system. AS regards the constraint RP. the learner has tO acquire something similar to Hr. But H1 IS a fairly simple hypothes~s that does not seem to require induct=on on extenswe hngmstic data.</Paragraph> <Paragraph position="1"> Finally, as we have shown =n the previous section, the boundeQness of the flow of information ol a orocessmg system leads directly to ~he locality orooerty of the SOT. The partTcular linking of S and E points as stipulated by the SOT, however, is a parameter of the iJnwersal Grammar that has tO be fixed.</Paragraph> <Paragraph position="2"> What about the second sub.question? How do speake~ ~earn to pair SRE conhguratlons wllh the basic tenses? There are 24 possible SRE configurations seven of which get grammat,calized. Here I want to prooose a principle of marKeOness ol SRE structures that has a natural computational motivation.</Paragraph> <Paragraph position="3"> Let us recall our restrictive temporal logic of instantaneous interval with one primitive relation, <, and three derived relations: <, >, and >. Represent a SRE configuration as follows: If we assume that labehngs of the third type corresPOnd tO the unmark, ed SRE configurations, the following division of unmarKeO and marked configurations is obtained: There are only eight unmarked tense structures corresponding to the sixteen SRE netwo~ configurations of type 3 because a tense structure can be interpreted by more than one network rebresentations, e.g., the Past Perfect (E_R_S) has the tollowing two configurations: The interesting result is that five out of the six basic tenses have unmarked SRE configurations. This agrees largely with our pretheoretlcal intuit=on that the SRE configurations that correspond to the basic tenses should be more &quot;unmarked&quot; than other possible SRE configurations. The fit. however, is not exact because the future perfect tense becomes the marked tense in this classification.</Paragraph> <Paragraph position="4"> Another prediction by this principle of markedneas is that both the simple future (S_R.E') and distant luture (S_R_E) are unmarked. It would 0e interesting to find out whether there are languages =n which the distant tuture actually gets grammat=calized.</Paragraph> <Paragraph position="5"> The final point tO be made =s about the second type of labelmgs. There are two Other possible ways of grouping the laOehngs: (1) given SR and SE. those labehngs ~n winch RE ~s constrained, and (2) given SE and HE. those in which SR is constrained. But these types of grouping are less likely because they would yield me s~mple present tense as a marked tense. Thus. they can be ruleO out iOy relatively few linguistic data.</Paragraph> </Section> </Section> <Section position="7" start_page="23" end_page="25" type="metho"> <SectionTitle> 3. Verb Aspect </SectionTitle> <Paragraph position="0"> In cons=clenng the problem of tense, we have restricted ourselves to a subset of Aliens temporal logic, namely, using a temporal structure <:T._<> with hnear oraenng of time points. TO make use of the full Dower of Allen's temporal logic, we now turn to the problem of verb aspect.</Paragraph> <Paragraph position="1"> The two mare problems of the study of verb aspect are the correct charac!erizat~on of (1) the three funclamental types of verb predtcatlon according to the situation types that they signify .. state, process and event, and (2) the p(=rspectwes from which a situation ts viewed, or its truth evaluated -- s~mpte or progreSSive. 6 in the first part of his paper. Allen attempts to prowde a formal account of *he state/process/even', d~s~mctlon using a temDoral logic. However. I beheve that htS charactenzahon faC/ls to capture welt.Known patterns of tense =mot;cations, and does not make the distinction ioetween situation types and perspective types funclamental to any adequate account of verb aspect. In the next 3ect=on. I will present some data that an,/ theory of verb aspect must be able to explain.</Paragraph> <Section position="1" start_page="23" end_page="24" type="sub_section"> <SectionTitle> 3.1 Data </SectionTitle> <Paragraph position="0"> Sentences containing clauses connected by a connective such as &quot;when&quot; have different aspect tnterpretat~ons depending on the s~tuatlon types and perspective types revolved.</Paragraph> <Paragraph position="1"> 6. Some of tl~ oener worlu~ are: Vcmdledr/. C~mne78. ~78. ?. It ~ ofllm been ~ OUl trill some Slal~ves do ta~e the oro~'es..~ve form. E.G., &quot;I am rnmkmg aOoul U~ exam.'. &quot;The doctor ts se~ng a pauenl.&quot; Ploweves,. a ~lut=l~lC/~ slucly ~ ~ that ~ tam*~ar stal,ve= rarely occur ~ln the prl)gress~ve aspect -. ~ thin 2% ol me lm~ (01,1~=3. secUon 2.2) {a) X C Y ,,.-* Xd Y V XsY V Xf Y (b) X C Y *-, X C Y V X e~ualY (c) mom(t) &quot;.-. t is an instantaneous ,nterval, i.e., consists of a smgle moment of time (d) per(t) '-- t is a non-instantaneous interval 8 where X and Y are generic symbols denoting state, event or process.</Paragraph> <Paragraph position="2"> (PROG): OCCUR(PROG(v,t)) -- morn(t) A ~ OCCUR(v,I) A (3 r)(t d t' A OCCUR(v,t')) 9 The progresswe aspect ss the evaluation of a situation from an interior oOmt t of the s~tuatlon which has the prooerty that though the sentence ts not true at that instantaneous ~nterval, ~t =s true m a nonqnstantaneous ~nterval r properly containing t. (Sl): OCCUR(s,t) -- (V t')(mom(t') A t' C t -- OCCUR(s,t')) A state verb is true at every instantaneous interval of t. The clefmitlon is slmttar to Aliens H. 1 (Allen84, 13.130). The following theorem shows that state verbs do not occur with the progressive aspect.</Paragraph> <Paragraph position="3"> '. contradiction. -t This theorem raises the tollow=ng quest=on: Why do some statlves occur w~th the orogresswe? I th~nK there are two answers. First, the verb in question may nave a use other than the statwe use (e.g. &quot;have&quot; is a statJve when tt means &quot;possess=on&quot;, and not a s,*atlve when it means &quot;experiencing&quot; as ~n &quot;John =s having a good time tn Paris.&quot;) Second. the English progressive may have a second meamng m addit,on to that cnaractenzed by PROG above. A freouent usage of the progresSwe =s to and=care short duration or temporariness, e.g., m &quot;They are hying m CamDrldge&quot;/&quot;They live =n Cambridge&quot;.</Paragraph> <Paragraph position="4"> 8. This SeCtIOn loenehL~ from the Ins~lhtS o! ear~ Taylor (&quot;rayldrT~. 9 & rewewet O! this oaOer po,nts out tnot me PI::IOG axiom seems to imDty tRat if something IS IO I~rOCJtlL~, II f'flg..~l complete. Thus. ,f Max is Oraw,ng a circle. II'=en at some. tuture time. ne must nave drawn the cIn:le. This =nt~ence =S clearty false because ;~efe ~ noth,ng contradiCtOry aJoou! &quot;Max was Orawmg a ca:tie Out he never drew ,t.&quot; For ,ns\[aoce. Max ml(Jnt su!tef a heart altaclL anti ~J auOOe~y. This =met.ante problem of the orogressNe 'orm ot a evenl veto =s xnown as If~ ,rnDertectlve paraoox in the hteralure One way oul is to Oeny mat ~a, was really drswmg a circle wflen ne oleti Rather ne was drawing sornelhmCJ ~'hlCh woulo nave deed a circle had I~t not d~C/l. This type ot analySiS would involve some machinery trom'Posslote WOlIO SemanUc$.</Paragraph> <Paragraph position="5"> A process verb can be true only at an interval larger than a single moment. This property differs crucially from mat of the statwes. (Pl): OCCUR(p,t) -- per(t) (P2): OCCUR(p,t) -- (V t')(per(t') A r C_ t -- OCCUR(p,t')) The following theorem shows that for a process verb, the progressive verb form entails the perfect form.</Paragraph> <Paragraph position="6"> Let t&quot; be the interval \[m 1 .m2\] Then. we have t&quot; ( t and t&quot; C t'. By (P2). we have OCCUR(p,t&quot;). That is, 0 has occurred. --I. The charactenzat,on of process verb by Allen (ms O.2) is less sat=slactory because ~t combines both the notion of Drogresswe asDect (his &quot;OCCURRING&quot;) and me process verb into the same axiom Furthermore. the difference between me predicate &quot;OCCUR&quot; and &quot;OCCURRING&quot; ~s not adequately exolamed in his paper.</Paragraph> <Paragraph position="7"> An event verb shares an ~moortant proDerty with a brocess verb. namely. ,t can be true only at a non.instantaneous interval. (El): OCCUR(e.t) -- !bet(t) (E2): OCCUR(e.t) -- (V r)(per(t') A r C t -- &quot;~ OCCUR(e,r) The following theorem snows that the ~rogresslve form of an event verb entads the negal~on of the perfect form.</Paragraph> <Paragraph position="8"> (E-THEOREM): OCCUR(PROG(e.t)) -- '-,(3 r)(per(t') A r< t A OCCUR(e,t')) Proof AS in the ~roof of (P.THEOREM). we can find a non-~nstantaneous interval t&quot; such that t&quot; < t and t&quot; C t' But |or any such t&quot;. we have OCCUR(e.t&quot;) Pecause of (E2). That is. it cannot be the case t11at e has occurred. --I.</Paragraph> <Paragraph position="9"> Again the crucial property (El) is not captured by Allen's charactenzat=on of events (ms O.1 ).</Paragraph> </Section> <Section position="2" start_page="24" end_page="25" type="sub_section"> <SectionTitle> 3.3 Constraint on temporal interpretations involving When </SectionTitle> <Paragraph position="0"> To account for the variety of aspect interpretations as presented in section 3.1.2, I propose the following constraint on situation/perspective type: (C-ASPECT\]: Let &quot;dynamic&quot; stand for a process or event. (a) simple/dynamic .-* morn(t) (b) simple/state ..- per(t) (c) progressive/dynamic -.-* per(t)/k _C PerspeCtive is a way of looking at the situateon type. For process or event, the simple aspect treats U~e situation as an instantaneous interval even though the situation ~tself may not be instantaneous. For state, the simple aspect retains its duration. The progressive aspect essentially views a process or event from its inter=or, thus requiring a stance in which the situation is a non.instantaneous interval and the admissible temporal relationship to be the C_ relations, i.e., s, s~, I, fi.d. di, eoual. Let me show graphically how C.ASPECT accounts for the</Paragraph> </Section> </Section> <Section position="8" start_page="25" end_page="25" type="metho"> <SectionTitle> XXX XXX XXXX XXX XXXX YYY YYYY YYY YYYY YYY XX XXXX YYYY YY 4. Conclusion </SectionTitle> <Paragraph position="0"> In this paper, I nave exam=ned two problems regarding linguistic semantics: tense and asDect. Important relationships between al~s;ract constra,nts governing lingu=st,c behavior and a computational scheme to reason aDout temporal relationships are discussed. In particular, I have shown that certain formal constraints, such as the Linear Order Constraint on tense, fall out naturally as a consequence of some computational assumptions.</Paragraph> <Paragraph position="1"> The interesting result =s that this formal constraint need not be learned at all, Another important role of a representation scheme in explaining phenomena that exist on a entirely different -. linguustic -- level is illustrated by the formulation of the C-ASPECT constraint to account for ~nterpretatlons of sentences conta,ning temporal connectwes.</Paragraph> <Paragraph position="2"> The study of linguistic semanhcs also sheds light on a representation of tJm~ hy reveahng the fundamental distractions that must be made, e.g.. a tensed sentence revolves three distract time points, and the aspectual interpretations reclu~re instantaneous/non-instantaneous ~nterval distinction.</Paragraph> </Section> class="xml-element"></Paper>