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## Re: [ontolog-forum] Time representation

 To: "[ontolog-forum]" paola.dimaio@xxxxxxxxx Mon, 21 Jan 2008 17:46:10 +0700
 ```John as you are being so kind to spell it out for us in plain language...    (01) what is the accepted syntax for pTim can pTim be a timestamp? is there a prescribed format for time/date in ikl    (02) thanks P    (03) On Jan 21, 2008 2:18 PM, John F. Sowa wrote: > John B., > > Some answers to your questions: > > > 1. Is the interpretation of [Proposition: p'] true if p' is true > > and false otherwise? > > Actually, it's more primitive than that. It's true if p' is a > proposition and false if p' is not a proposition. > > In effect, a conceptual graph g is true or false by itself (just > as any formula in any version of logic). But when you surround > g by a box with a type label, the only thing that is asserted > is that g is of that type. (If it's not of that type, as in > [Situation: g], then type coercion causes g to be interpreted > as a statement of a proposition that describes the situation.) > > That corresponds to what the QUOTE operator does in Lisp: it > prevents the following expression from being evaluated. In order > to force the evaluation in Lisp, it's necessary to use another > operator called EVAL: > > (EVAL (QUOTE s)) is equivalent to s by itself. > > In conceptual graphs, the Asrt (assert) relation has that effect: > > (Asrt [Proposition: g]) is equivalent to writing g by itself > on a 'sheet of assertion' (Peirce's term). > > > 2. What about the [Situation *s] graph? This is true if there > > in fact existed a situation on 20 January 2008 that made > > proposition p' true? > > That concept node, by itself, simply says that there exists a > situation, and s is used to label it. It maps to the following > formula in CLIF: > > (exists (s) (Situation s)) > > To say that there existed a situation on that date that made p' true, > you would write > > [Situation: *s p'] (PTim ?s "20 January 2008") > > By type coercion, the concept node on the left would be expanded: > > [Situation: *s] [Proposition: *x p'] (Dscr ?s ?x) > (PTim ?s "20 January 2008") > > This says that there exists a situation s, there exists a proposition x > stated by the graph p', the description of s is x, and the point in time > of s is 20 January 2008. Following is the corresponding IKL: > > (exists (s x) (and (Situation s) (Proposition x) (= x (that p)) > (Dscr s x) (PTim s "20 January 2008")) > > > 3. In the context framework you mentioned the other day, with the > > triples, you defined (T1,X,T2) as a T1 = a bounded text, X = a > > context, and T2 = axioms showing the relation of T1 to X. > > What would be an example of an axiom that relates p' to > > (PTim ?s, "20 January 2008")? Does this simple example need any? > > The graph p' would correspond to the text T1. The situation s would > be the context X, in terms of which the T1 is interpreted. The text > T2 would be some axioms stated in some version of logic (which could > be stated in conceptual graphs, IKL, or any other suitable notation) > that would say how the PTim relation is supposed to relate any > situation to any date (of which s and "20 January 2008" are examples). > > John Sowa > > > > > _________________________________________________________________ > Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/ > Subscribe/Config: 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 Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx > >    (04) -- Paola Di Maio School of IT www.mfu.ac.th *********************************************    (05) _________________________________________________________________ Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/ Subscribe/Config: 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 Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx    (06) ```
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