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• CommentRowNumber1.
• CommentAuthorUrs
• CommentTimeJul 22nd 2011

the brief idea at kinematics and dynamics

• CommentRowNumber2.
• CommentAuthorzskoda
• CommentTimeJul 23rd 2011

Cf. the idea section of classical mechanics where the classical division into statics, kinematics and dynamics is also commented on.

• CommentRowNumber3.
• CommentAuthorTobyBartels
• CommentTimeJul 23rd 2011

I added a bit to kinematics and linked to the pictures from dynamics.

• CommentRowNumber4.
• CommentAuthorUrs
• CommentTimeJul 23rd 2011

Thanks, looks good!

• CommentRowNumber5.
• CommentAuthorUrs
• CommentTimeJul 23rd 2011

I have started two new subsections at kinematics and dynamics: one on formalizations of the notion, and the other on examples, indicating what kinematics and dynamics corresponds to under quantization of classical data.

Much more discussion could be given here eventually, of course.

• CommentRowNumber6.
• CommentAuthorzskoda
• CommentTimeJul 24th 2011

Kinematics and dynamics are not necessarily about classical mechanics, they are well defined in quantum mechanics as well. Statics as well.

• CommentRowNumber7.
• CommentAuthorUrs
• CommentTimeJul 24th 2011

Kinematics and dynamics are not necessarily about classical mechanics, they are well defined in quantum mechanics as well.

Zoran, I have a similar problem with the apparent disagreement of this sentence as I had before in another thread: I can’t see which statement it is that you are disagreeing with. Nobody seems to have said that kinematics and dynamics is “necessarily about classical mechanics”. On the contrary. In the entry you find first a general definition in mechanics, then a formalization in quantum mechanics, and finally an example that illustrates the concept under quantization.

If you disagree with anything, please make clear what it is.

• CommentRowNumber8.
• CommentAuthorzskoda
• CommentTimeJul 24th 2011

I did not say that I disagreed.

• CommentRowNumber9.
• CommentAuthorUrs
• CommentTimeJul 24th 2011

Oh, I see. Let’s try to sort this out generally, then, it seems to me that you and me repeatedly misunderstand each other in this way, which is unfortunate.

So the thing is that if I start a thread here and then you leave a comment saying “X is not Y” then I assume that you are taking it that I asserted that “X is Y” and are disagreeing with it. But maybe that’s not what you mean. I’ll try to remember it next time.

• CommentRowNumber10.
• CommentAuthorzskoda
• CommentTimeJul 24th 2011
• (edited Jul 24th 2011)

Yes, you repeatedly ask me for the purpose of some comments and the purpose what I wanted in some $n$Lab entry. I am not much of a goal oriented personality and this usually does not make sense to me. If I see that I can say something to emphasize, to complement or to clarify in the discussion I say it; it is most often more about the discussion in the thread than about the corresponding $n$Lab entry. Usually the motivation to everything to what one says in a thread is associated to something said earlier in the thread, or what is reminded by that, but not with big intentions which you are looking in there. It is useful however to have in mind what has been said in the very thread (in my view, even more than what is said in the $n$Lab).

One should also have in mind that for somebody when remarking about the $n$Lab comment that it is appropriate to be asked to implement it himself, as it is your mantra. I mean it is good mantra in some other contexts, like the large scale complaining of people who are not involved. But in $n$Forum it is inappropriate because one person is at some point thinking deeply and concentrated about one circle of entries. Others are concentrated on some other topic in the moment. They may have background or read before on the topic and can give useful pointers to literature, to forgotten aspects, to possible errors. It is easier for the person who is currently working on the entry to take notice of such remarks, then for the person who remarked in passing, to switch his daily subject completely, and trash an afternoon to switch the topic and to implement himself. Of course, the person who currently works on an entry may not find the remark clear enough to absorb it, may disagree or may simply not have even a single minute to do little adjustments. So the remark is not obligatory for anybody. But still, I find be sent to do it myself and to be reminded to put the remark into $n$Lab rather than noting it in $n$Forum (for everybody to see, and even oneself to come back to it much much later!), somewhat of a burden which messed many of my afternoons when I accepted to do the required homework, although it was not in the line of my needs at the moment. Those of us who work a lot on adding things to $n$Lab should not be pressed to do that in addition whenever giving a side remark which we find useful already at the level of a remark.

Personally, back to the thread, I think that the entry kinematics and dynamics does not need to stay separate as $n$Lab topic (though I do not have a strong opinion o such). It would be more systematic to have the distinction as a paragraph at mechanics while the separate features of each should be at single topic entries kinematics and at dynamics, classical kinematics, etc. Especially when statics is also traditionally contrasted to the other two. The advantage of $n$Lab over the cafe is to have things classified by single notion rather than by the noncanonical discussion title.

• CommentRowNumber11.
• CommentAuthorTodd_Trimble
• CommentTimeMar 4th 2019

Recently I was reading on the Bohr topos which led me to the kinematics and dynamics article. Just wanted to recall to attention the ellipsis under AQFT, in case anyone wants to fill it in. No rush, obviously.