jan...@gmail.com> wrote:
> He seems to be advocating the usage of two words, one for
> "turning" and one for "rotating", which I advocate.

Could someone explain why the same word can't be used for both?

The difference is subtle, but more apparent in Lojban place struc= ture. For "rotate," we want a place structure focusing on a continuing rota= tion, so we focus on the direction of rotation and axis. For "turn," we wan= t a place structure focusing on a short rotation, so we focus on the initia= l and final "angular positions" -- which way the object is facing at the be= ginning and end. Robin's example was saying "I turn to face you." -- The on= ly way I can think of to say that now is something like {mi vo'a cargau mu'= i lo nu do mi crane}, which I guess isn't too terrible, now tha= t I think about it. In fact, {cargau} seems really good for "opening a door= " or "unscrewing a bolt" which I believe were other discussed problem sente= nces.

Is that part of the= proposed difference?

I'm pretty sure it is.

"zulcarna" and "pritycarna" have been used before for laevorotation
and dextrorotation. Why are they inadequate?

That sounds like gibberish to me, but I understand th= e fundamental issue to be that carna3 had a pretty unknown usage since it r= equires an arbitrary "clockwise" or "counterclockwise" implication to be us= eful. Thus, any lujvo based off it are equally arbitrary, and redefining th= e gismu seems advantageous. I'd like to take a step back for a moment and m= editate on why we're making a new word at all. There's a lot here to digest= , and a lot that doesn't make sense.

aionys said a= while ago that changing {carna} to the "turning" definition would actually= be more likely to fix previous usage:

More often, it's used in the sense "x1 turns towards x3", as i= n {mi carna fi lo mi zdani vorme}.

I looked over the corpus link he provide= d and couldn't find any good, clear uses of carna2/carna3 that didn't seem = like someone testing usage / asking about usage. In other words, it seems t= o me like everyone's been in the same boat of "umm... how do I use this, ex= actly?"

doi aionys, could you discuss the exact examples that pre= clude the definition of {carna} we somewhat like, that "x1 rotates counter-= clockwise about axis x2 from perspective x3"? Or which specific examples su= pport the "turning" definition? (I only found one like that, and it seemed = like Robin using it, wanting it to mean that or thinking it did.)

I feel that this is critical to this discussion:

If previous usage of place structure is minimal to nonexistent, the= n it makes perfect sense to redefine carna as close to "x1 rotates counterc= lockwise from perspective x2 about axis x3" as possible, so as to not break= existing lujvo. Then {cargau} could be used for "turning" in the sense Rob= in wants. I'd also toss about the idea of using {barcarna} fa'u {nercarna} = for "revolve" fa'u "rotate".
If previous usage of place structu= re actually points to a particular definition significantly, then we should= take that into account accordingly.

ji'a doi aionys, I think that the idea of multiple axes is very = interesting. So you know, how you are thinking about using the axis place m= akes no sense to me from my physics background, but I find it very interest= ing as it actually might make the axis place useful. Also, it seems mathema= tically consistent. With current place structure, but your axis usage, it s= eems that:

{carna= lo bartu} refers to revolution

{carna lo nenri} refers to rotation

{carna re lo bartu} refers to elliptical revolution=

{carna re lo nenri} re= fers to ... elliptical rotation? That actually kind of makes sense, in a ve= ry weird way.

{carna ci= da} refers to... what? I'm looking into this. Thoroughly intriguing. The e= xtension I'm using now gives a beautiful shape, IMO. (That is, in 2-dim, gi= ven "axis" points a, b, c, and the scalar r, the set of {x for which |x-a| = + |x-b| + |x-c| =3D r} gives something that looks like an ellipse with thre= e foci.) I made some pictures of circles, ellipses, and 3-foci things with this extension.

Also, what about the issue that= axes are lines? The ellipse extension assumes parallel lines -- what would= nonparallel lines indicate? (It doesn't have to indicate anything, mind yo= u. It is mathematically interesting, however.)

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