Re: [lojban] Re: Direction of Rotation

[la gleki <gleki.is.my.name@gmail.com>]

On Saturday, August 25, 2012 1:46:06 PM UTC+4, Robin Powell wrote:
> On Fri, Aug 24, 2012 at 01:25:56PM +0200, selpa'i wrote:
> [snip]
> > Thus, since all we need to define the direction is an axis ML,
> > which has an inherent orientation as mentioned above, and a point
> > B *relative* to our starting orientation towards AL', {carna},
> > which has both these as x2 and x3 respectively is plenty to
> > express clockwise and counter-clockwise motion. carna2 will not
> > need to be specified for bodies that overlap almost completely
> > with the axis ML, like for instance a standing human being, and
> > for objects like a disk that's lying flat on the plane, we only
> > need to choose the polarity of vector ML.
>
> The problem is that you've ignored the hard part: how to specify the
> vector ML.
>
> We have, to the best of my knowledge, no compact way to do that *at
> all*.  At the end you talk about specifying only the polarity; I
> don't even know how to do *that* in compact fasion.

Yes, that's the whole thing. Someone said that i was trying to introduce an extra  term  called "line of sight" to the schemes.

But the fact is that there is always an observer.

look at those terms: "higher" (according to whom????), "to the left" (who sees that it's to the left???)

{ti pritu mi} - what does the word {mi} really mean here? What if I stand on my head? Then it would immediately change to {ti zunle mi}. So what does the word {pritu} really denote???? How can you explain it?

The answer is that 1. {mi} is a vector. And 2. {mi} determines what is left, right, above and below.

Therefore, if you want to specify direction of rotation you will come up with {left/right/above/below} anyway. By the way, above/below is automatically derived from left/right and vice versa so we need only two of those terms.

Human eye automatically tags any object as having upper and lower parts defined by a horizontal (according to the eye) line extending for left to right

We can use either up/down when describing right-hand rule or left/right. Those are two equal options. It's all the matter of convenience and conciseness.

> How do you specify "rotate the monitor clockwise as viewed from the
> front" versus "rotate the monitor clockwise as viewed from right
> side"?

{lo tivni cu rotro lo pritu mi} = "rotate the monitor clockwise as viewed from the front"

{lo tivni cu rotro lo pritu lo pritu be mi} = "rotate the monitor clockwise as viewed by someone standing to the right side of me" (really a very rare case. E.g. I see the monitor in profile and you are standing to the right of me but in many more real cases I'd say {rotro lo pritu do} so brevity is not so relevant here).

If you feel that you can't define {rotro} in a human-like form just define rotro2 as lo pritu for clockwise and lo zunle as counterclockwise.

After all I just showed you that {pritu} is a really mysterious word if you don't know how {mi} works (and labels reality).

> I have some possible solutions in mind, but I'd like to hear other
> people's first.
>
> -Robin
>
>
> -- 
> http://singinst.org/ :  Our last, best hope for a fantastic future.
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