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## Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as

 To: ontolog-forum@xxxxxxxxxxxxxxxx John F Sowa Thu, 19 Jun 2014 12:30:26 -0400 <53A31022.8090007@xxxxxxxxxxx>
 ```Tara and Pat,    (01) I agree with Pat that you don't need a 'that' operator for reasoning about time. But I agree with Tara that you need 'that' for many other purposes.    (02) For the first point, I recommend the following book, which shows how a sorted FOL (with time as a sort) can be used to represent anything in temporal logic or dynamic logic:    (03) Gergely, Tamás, & László Úry (1991) First-Order Programming Theories, Berlin: Springer.    (04) They show that you can't reduce temporal logic to dynamic logic or vice-versa. But you can translate either one to a version of FOL that quantifies over time. A sorted logic is desirable, but not required.    (05) TA > (forall C P > (if > (cl:comment 'C employs P' > (employs C P) ) > (exists T > (cl:comment 'It holds during some time interval T that C employs P' > (during (that (employs C P)) T ) > ) ) )    (06) To express this sentence without IKL, you could use a 2-argument and a 3-argument version of 'employs':    (07) (forall (C P) (if (employs C P) (exists ((T Interval)) (forall ((t Instant)) (if (isin t T) (employs C P t)) ))))    (08) Comment: If C employs P, there is an implicit interval T, and for all instants t in T, C employs P at t.    (09) But a more general option would be an entity of type Employ, which may have any number of qualifiers attached to it. For required qualifiers, you could state appropriate axioms:    (010) (forall ((x Employ)) (exists ((T Interval)) (forall ((t Instant)) (if (isin t T) (at_Time x t)) )))    (011) Comment: For any instance x of Employ, there is an implicit interval T, and for all instants t in T, x occurs at time t.    (012) With this representation, an assertion that C employs P could be represented with "case relations" as    (013) (exists ((x Employ)) (and (Agent x C) (Theme x P))    (014) With the above axiom, this would imply that there exists such an interval T. The English verb 'occurs' in the comment suggests a more general representation: Define Employ as a subtype of Occurrent that persists for some interval.    (015) You could say that the entity of type Employ is a reification. But I would rather say that it's just an entity of type Employ.    (016) Re Tara's examples about using 'that' to represent possibility, prohibition, knowledge, etc.:    (017) PH > all they do is put the entire burden of representing their meanings > on the relation names... and implicitly make a claim that the relevant > concepts ... are indeed properly representable as relations between > propositions and something else.    (018) Something like the IKL 'that', McCarthy's 'ist', or the methods of situation semantics for relating 'infons' to situations is an important first step. But you need a full-blown theory, not just a few axioms. That's still a major research area.    (019) PH > BTW, did I ever send you my ideas on how to reduce IKL to CL by > eliminating "that" constructions recursively? I would be interested > in your reactions.    (020) That report is important. Could you put it on your web site?    (021) John    (022) _________________________________________________________________ Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/ Config Subscr: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/ Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx Shared Files: http://ontolog.cim3.net/file/ Community Wiki: http://ontolog.cim3.net/wiki/ To join: http://ontolog.cim3.net/cgi-bin/wiki.pl?WikiHomePage#nid1J    (023) ```
 Current Thread Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, (continued) Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, Kingsley Idehen Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, David Whitten Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, Rich Cooper Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, Barkmeyer, Edward J Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, John F Sowa Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, Rich Cooper Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, John F Sowa Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, Rich Cooper Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, Pat Hayes Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, Tara Athan Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, John F Sowa <= Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, Barkmeyer, Edward J Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, Mark H Linehan Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, John F Sowa Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, Richard H. McCullough Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, Kingsley Idehen [ontolog-forum] Become the Ontology SME, John Bottoms Re: [ontolog-forum] Become the Ontology SME, rrovetto Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, Barkmeyer, Edward J Re: [ontolog-forum] Requesting Opinions on the Benefits of Predicates as Nodes, John F Sowa [ontolog-forum] Reducing IKL to CL (was: Re: Requesting Opinions on the Benefits of Predicates as Nodes), Pat Hayes