wrong duplicate assignement, and nested duplicates

This question is not a duplicate of the one quoted , and further more, the one quoted is also called a duplicate .

I suppose as the data base increases this nesting of duplicates will increase, and some thought should be given before assigning duplicates.

The question under discussion is not talking about "touching" but about the infinity coming from the 1/r electromagnetic potential

I will flag it for opening because it is a bad picture of the site, sending readers on a random walk.

• OP was basically asking whether two protons really do touch when they collide as the force of repulsion increases & the line-integral increases due to the inverse proportionality to $r.$ The other question was also asking the same thing. – user36790 Nov 10 '15 at 5:20
• @user36790 Yes, but the answer to two protons colliding is not the electromagnetic constructs of the duplicates, it is that the proton has constituents, and that the strong force exists. Touching is a different problem correctly addressed by the duplicates. – anna v Nov 10 '15 at 5:56
• That response should have to come from OP himself if he really thinks his question is different which it is as you are saying. However, let OP decide how he changes the question to make his query different from that marked one. – user36790 Nov 10 '15 at 8:42
• I agree that this one is not a duplicate - I just seconded your reopen vote. – Emilio Pisanty Nov 10 '15 at 11:41
• @anna v : I concur. This is an example of over-zealous close votes by people who are so hasty they can't even be bothered to link to the duplicate of the duplicate. It seems to be the same names doing it, and all too often I click on the alleged duplicate and see that it isn't really a duplicate, or I see a non-answer, or a wrong answer. – John Duffield Nov 10 '15 at 13:46

I have never understood nested duplicates. I agree with Anna that it sends a pretty bad picture of the site, and it is completely unnecessary. When voting to close a question A, it is perfectly clear that the proposed duplicate (call it B) is itself a duplicate (of, say, C).

There's a few situations that could cause this:

• C contains answers that answer the concerns in A. The correct course of action is to mark A as a duplicate of C, directly.
• B contains answers that address the concerns in A, and the answers to C don't, but those concerns are indeed in the question in C. B and C should probably be merged - this is done by moderator action through a flag.
• B contains answers that address the concerns in A, and those concerns are not relevant to the question in C. B and C are likely to not actually be duplicates, so B should be reopened.

There's no situation where it's advantageous to have a chain of duplicates. Moreover, doing that deprives C of having A on its Linked sidebar, which makes it harder to gauge its importance as a frequently-duplicated question. If the intent is to make B known to the readers of A, it is still in the Linked sidebar of C and one can still drop a 'Related: ...' comment on A if really necessary.

Seriously, I don't get nested duplicates.

• I downvoted because I don't think that nested dupes are bad or shine any negative light on this site (see also this Mother Meta post for one POV of why it can be beneficial). – Kyle Kanos Nov 10 '15 at 16:15
• @Kyle Fair enough. I disagree with your link and with its applicability here (it being much easier to reopen duplicates one thinks are incorrectly marked here than on, say, SO) but that is as it may be. – Emilio Pisanty Nov 10 '15 at 16:23

On the broader question of duplicates of duplicates, I have occasionally VTC'd a question as a duplicate of a question that was already closed as a duplicate. I've done this when I thought both previous questions added value because they and their answers had different emphases. By voting this way I am recommending the OP will gain value from reading both previous questions.

I don't see anything wrong with doing this. The argument that it looks bad strikes me as irrelevant. This is a site for professional physicists, where by professional I mean people who know some physics and are willing to work to learn more. Despite the recent upsurge in questions from well intentioned non-physicsts it is the members who are (and I quote from the tour) active researchers, academics and students of physics and astronomy that my activities here are aimed at. Such people won't have any problem following a duplicate chain and indeed might find it entertaining reading.

To dispose of the specific case Anna raises:

Why can protons collide? is a duplicate of Do particles ever touch each other during a collision? and closing it as a duplicate is justified. However Do particles ever touch each other during a collision? is not a duplicate of What does it mean for two objects to "touch"? - I note I made a comment saying as much at the time.

The appropriate resolution of this is to leave Why can protons collide? closed, then reopen Do particles ever touch each other during a collision? and add an answer explaining what physicists mean by scattering.

• I think that if you encounter a "duplicate chain" where the answers have different emphasis and are all worthwhile reading, the proper course of action would be to raise a mod flag and ask them to merge all of those to a single spot instead of lengthening the chain. While I am able to follow a chain, I'd much prefer the convenience of just scrolling through the answers. – ACuriousMind Nov 10 '15 at 14:39
• John, I disagree with you in this. There is no "touching" in the question, and it is really asking about the coulomb potential between two like charges, note "two" not fields and collectives which "touch" involves. The OP is asking about the limit. Furthermore, the answer in the first duplicate does not answer the OP's question. What good is it to mark as duplicate something where the answer is tangential and not relevant. – anna v Nov 10 '15 at 14:48
• Physics.SE answers come up in google searches, sometimes first. Is it a good inducement to follow the site through duplicates of this format? – anna v Nov 10 '15 at 14:51
• @annav: I have voted to reopen Do particles ever touch each other during a collision?. If/when it is reopened I will add an answer that addresses both questions. – John Rennie Nov 10 '15 at 15:56
• @KyleKanos: ??? I've voted to reopen Do particles ever touch each other during a collision? because I don't think it's a duplicate of What does it mean for two objects to “touch”?. If/when the question reopens I trust it will stay open. – John Rennie Nov 10 '15 at 16:07
• @JohnRennie: whoops, misread the "appropriate action" bit. sorry (too many titles & links) – Kyle Kanos Nov 10 '15 at 16:10
• @JohnRennie : note that Do particles ever touch each other during a collision? contains this sentence: "This means that a charged particle, such as an electron, is composed of not only itself but also a field of photons". This is absolutely wrong. Note anna v's sentence here: "virtual particles exist only in the mathematics of the model". I object to a vote-to-close when the answer to the alleged duplicate contains a glaring error. – John Duffield Nov 10 '15 at 17:39

I think you have a point. Though I'd say your last line ("...because it is a bad picture of the site, sending readers on a random walk") is hyperbolic - in the language sense, not the math sense, of course. I don't feel so strongly about it, and in particular not strongly enough to override the community votes.

I do believe the question would be improved if it were edited to explicitly identify apparent duplicates and explain why it's not already covered by them. This is, of course, always recommended any time you think a question has been wrongly marked as a duplicate.

• IMHO what gives a bad picture of the site is closing down good questions by saying they're duplicates when they aren't, particularly when the answers on the duplicate are non-answers, or even wrong. I fear the "community" is being overly hostile here, and that this is an issue that requires your attention. – John Duffield Nov 10 '15 at 13:49