* Tuesday, 2014-10-21 at 19:16 -0300 - Jorge Llambías <jjllambias@gmail.com>: > On Mon, Oct 20, 2014 at 10:06 PM, Martin Bays <mbays@sdf.org> wrote: > > * Saturday, 2014-10-18 at 22:27 -0300 - Jorge Llambías <jjllambias@gmail.com>: > Not sure what I meant now. I think I meant that you couldn't do with most > functions (i.e. lo-functions) what you could do with the closed class of > LAhE-functions, in terms of scope. (You can do it indirectly by using the > prenex, of course.) Ah, I see. Then yes, na'u aside. > > But anyway: technically the class isn't actually closed, because of {na'u}! > > Would "na'u broda" be an open class of functions but not "lo broda"? "na'u" > seems to be an inside-of-mex equivalent of "lo". We could say that "lo > broda"="li na'u broda mo'e zo'e/zi'o". Plausibly. > > {ro danlu cu jbena gi'e ba bo morsi} > "ro danlu" has scope over "gi'e" so it would be: > > ro da poi danlu zo'u ge ge da jbena gi da morsi gi lo nu da morsi cu balvi > lo nu da jbena Good. Agreed (as far as the scope goes). > > If the logical connective isn't {je}, probably the tag relation should > > only apply when the connectands are both true, i.e. corresponding > > events/facts occur/hold. This seems sensible, and is supported by CLL > > Chapter 10 Verse 17.10. > > So ".i je nai [tag] bo" is always false? I meant rather that it would be equivalent to ".i je nai bo". > > Firstly, we need a way to assign an event/fact variable to a proposition > > without changing its semantics. {fi'o du} lets us do this; {fi'o du ko'a > > broda} means that broda occurs/holds and ko'a is equal to the > > event/fact of this. Let's make this a primitive in the logic, writing it > > as "=.", so e.g. "{ko'a}=. broda()". (So technically "[term]=." is > > a modal operator.) > > I had never considered "fi'o du", it sounds useful. Maybe we want "fi'o > ca'e du" if it's an assignment to a variable, rather than a claim. Or maybe > it should be "sei ca'e ko'a du'u no'a", although I'm not sure whether > "no'a" gets the right bridi. * Wednesday, 2014-10-22 at 00:30 +0200 - Ilmen <ilmen.pokebip@gmail.com>: } I think you need {ca'e} for assigning a referent to {ko'a} (otherwise it } would be an assertion "the bridi is identical to {ko'a}'s referent"), or } whatever is the correct way to explicitly assign a referent to a } pro-bridi without ambiguity. I didn't really mean it to be an assignment in that sense, although perhaps that could help. I did really mean that I want {fi'o du ko'a broda} to occur/hold iff (broda occurs/holds and ko'a is the event/fact of this). (I think from now on I'll just say "occur" and "event"; depending on our ontology of events, facts could just be special cases anyway - though I don't know if we want to require that.) } {fi'o} is maybe a little too vague for your purpose; I'd suggest {broda } xoi <http://jbovlaste.lojban.org/dict/xoi> ke'a ca'e du fo'a} which } would be semantically equivalent to {lo du'u broda ku ca'e du fo'a}, if } I'm not mistaken. Is {broda xoi xo'i [tag] ke'a} not equivalent to {[tag] broda}? > > (I write the above paragraph as if I'm sure it makes sense, but I'm not. > > If there are many events of brodaing in the situation, is {fi'o du ko'a > > broda} true when ko'a is any of those events, or only when it's the > > "intended" one? > > I would say it assigns to "ko'a" the intended ones, i.e. the ones you are > describing with this proposition. Plurally? Yes, that's another possibility. It would make things simpler if we took a bridi to describe to a single event for the purposes of tag handling (though of course allowing {lo mu nu limna} and so on). I suppose we have to allow it to describe kinds of events too, if we're to explain {roi} compositionally ({mu roi broda} -> "brodaing occurs five times"). But I can't think of natural example where a plural interpretation is necessary. Probably I'm just lacking imagination? > Then we can handle tagged conjunction by quantifying over events: > > ro danlu cu jbena gi'e ba bo morsi -> > > FA x1:(danlu(_)). EX x2. (x2=. jbena(x1) /\ (ba)(x2). morsi(x1)) > > ro da poi ke'a danlu ku'o su'o de zo'u ge fi'o du de zo'u da jbena > > gi ba de zo'u da morsi > > , which is I think a natural and useful way to interpret it. > > > > Now for connectives other than conjunction, I'm not seeing a neater > > solution than to "skim off" the TT case (if there is one); so e.g. to > > consider {broda .i na ja ba bo brode} to be equivalent to > > { na broda .i ja broda .i je ba bo brode}, where the tagged conjunction > > is interpreted as above. > > > > Not very pretty. I'd be happy to hear of alternative possibilities. > > The fact that it only works well with "je" suggests there's something wrong > with the "jek tag bo" construction. I don't know, the "TT-skimming" semantics seem to give useful results in at least some cases. Probably most usefully, {broda na .i ja ba bo brode} would mean "if broda, then afterwards brode". Then there's the {ja} case I referred to in CLL, which seems reasonable. For {jo}, it doesn't have an easy translation to english, but seems plausibly useful anyway; e.g. {do ba prije gi'o ja'e bo snada} -> "you will be wise and therefore successful, or neither". > > It's odd however to have to read "li no pi'i mo'e ro namcu cu du li no" > > > differently than "lo pilji be li no bei ro namcu cu du li no" > > > > Is it? I don't know. > > > > To analogise: I think the english pair > > "zero times any number is equal to zero" and > > "the product of zero and every number is equal to zero" > > conveys the two meanings, using roughly the same structures. > > But that's purely due to the different scopes of any/every, not to the > variation between times/product-of. If you had "zero times every number is > equal to zero" and "the product of zero and any number is equal to zero" > you'd get the opposite result. You're right for the second (a flexibility it would be nice for lojban to have), but I think "zero times every number is equal to zero" is just bad english; it can't have the opaque meaning. Which was my point. Martin
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