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Re: [lojban] Sounding of the {ROTATE} gismu (was Direction of Rotation)

On Monday, August 13, 2012 5:19:24 PM UTC-5, xorxes wrote:
On Mon, Aug 13, 2012 at 4:16 PM, djandus <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 structure. For "rotate," we want a place structure focusing on a continuing rotation, so we focus on the direction of rotation and axis. For "turn," we want a place structure focusing on a short rotation, so we focus on the initial and final "angular positions" -- which way the object is facing at the beginning and end. Robin's example was saying "I turn to face you." -- The only 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 that 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 sentences.
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 the fundamental issue to be that carna3 had a pretty unknown usage since it requires an arbitrary "clockwise" or "counterclockwise" implication to be useful. Thus, any lujvo based off it are equally arbitrary, and redefining the gismu seems advantageous. I'd like to take a step back for a moment and meditate 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 in {mi carna fi lo mi zdani vorme}.
I looked over the corpus link he provided 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 to me like everyone's been in the same boat of "umm... how do I use this, exactly?"
doi aionys, could you discuss the exact examples that preclude the definition of {carna} we somewhat like, that "x1 rotates counter-clockwise about axis x2 from perspective x3"? Or which specific examples support 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:
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 makes no sense to me from my physics background, but I find it very interesting as it actually might make the axis place useful. Also, it seems mathematically consistent. With current place structure, but your axis usage, it seems 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} refers to ... elliptical rotation? That actually kind of makes sense, in a very weird way.
{carna ci da} refers to... what? I'm looking into this. Thoroughly intriguing. The extension I'm using now gives a beautiful shape, IMO. (That is, in 2-dim, given "axis" points a, b, c, and the scalar r, the set of {x for which |x-a| + |x-b| + |x-c| = r} gives something that looks like an ellipse with three 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 you. It is mathematically interesting, however.)

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