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Synopsis and concrete practices

Everyone is thanked for their comments, and in view of the diversity of views expressed, I have converted this question to a community wiki.

Here is a working synopsis:

  • With regard to the alternative hyphenations Kron-ecker versus Kro-necker, the "advanced search" feature of Google Books establishes that both hyphenations are in common usage.

  • The rules of German-language orthography are sufficiently intricate, and the etymology of the name Kronecker is sufficiently obscure, as to provide well-founded justifications for either hyphenation.

  • No one has come forth with a set of standardized hyphenations for mathematician's names that is in-use by a major mathematical journal or publishing house.

In light of the preceding findings, one reasonable practice is the following:

  • Include in the LaTex preamble a list of problematic mathematician's names that (by default) forbids their hyphenation (this was Theo Johnson-Freyd's excellent recommendation):

          \hyphenation{Kronecker Riemann Spivak}

  • Upon the (rare) occasions that acceptable typography requires hyphenation of one of these names, then in the body of the manuscript optional hyphens can be inserted in the LaTeX file:

          \LaTeX optionally hyphenates Kron\-ecker Rie\-mann Spi\-vak

  • In placing optional hyphens, lend equal weight to common usage and correct orthography (recognizing that these can be ambiguous upon occasion).

  • Search methods help resolve problematic cases, for example the hyphenation Rie-mann is overwhelmingly preferred over Riem-ann.

And finally, we should all remember to be grateful to Donald Knuth, who gave us the wonderful tools that allow us to balance good orthography with good typography.

Original question

The question asked is:

Kro-necker versus Kron-ecker: which hyphenation is preferred?

Equivalently, in TeX/LaTeX should one include "\hyphenation{Kron-ecker}" in the preamble? Or should one simply accept the default TeX/LaTeX hyphenation "Kro-necker"?

A search of the tex-hyphen archives provides neither guidance specifically on "Kronecker," nor general guidance on preferred hyphenations for mathematician's names (except to show that there is a community of people who care passionately about these lexicographical issues).

Therefore, instantly "accepted" will be any MathOverflow answer that provides a standardized "\hyphenation{...}" file (including mathematician's names) from any respected mathematical journal or publishing house.

Although this question is perhaps not the most important ever asked on MatherOverflow, such a preferred-hyphenation list would be welcomed by me, and (IMHO) by many mathematical writers. For example, are there other problematic mathematical names?

Recognizing too that some folks are relatively indifferent to mathematical hyphenation, these folks can provide instruction and amusement by offering opinions on the question "Why has the usage of 'Kronecker' been increasing inexorably for the past fifty years?"

Google NGRAMS of Kronecker

As Mark Twain might have put it:

Any calm person, who is not blind or idiotic, can see that in the year 52,011 or thereabouts, every book produced by human civilization will consist solely of the sentence "Kronecker, Kronecker, Kronecker,…"

There is something fascinating about Google's Books Ngram Viewer. One gets such wholesale returns of conjectures, out of such a trifling investment of fact.

However, any opinions offered in this regard, no matter how erudite or amusingly stated, will not be considered as answers.

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closed as off topic by Martin Brandenburg, algori, Mark Sapir, Andreas Thom, Harry Gindi May 25 '11 at 12:12

Questions on MathOverflow are expected to relate to research level mathematics within the scope defined by the community. Consider editing the question or leaving comments for improvement if you believe the question can be reworded to fit within the scope. Read more about reopening questions here.If this question can be reworded to fit the rules in the help center, please edit the question.

Given that you're writing in English rather than German, shouldn't you be using English hyphenation rules rather than German ones? In which case, based on the pronunciation, it would be Kro-neck-er if you pronounce it with a long o, and Kron-eck-er if you pronounce it with a short o. – Peter Shor May 25 '11 at 1:37
That the location of a hyphen can matter is seen in the following examples: riders-hip, its-elf, code-pendents, lighty-ears, misty-ped, ong-oing, men-swear, skip-ants, re-ached, mans-laughter, cave-at. – Michael Hardy May 25 '11 at 1:47
We could choose the widths of book pages so that we don't need to hyphenate the word, at least from 52,011 onwards. – Douglas Zare May 25 '11 at 6:10
Peter Shor, actually I believe not. At least I was under the impression, but have not good reference to back it up, that words of foreign origin, in this case the German name, should be treated according to the rules of its language. – user9072 May 25 '11 at 9:58
To be honest, I am a bit surprised by your conclusion; after all there is one comment that says the hyphenation you now want to use is forbidden (Konrad Waldorf), and I argued at length (with references, one provided by somebody else in the comments) that Kro-necker is certainly admissible. As it is admissible to follow the pronunciation, and the pron. is referenced and nobody said it is different. If the pron. were Kron ecker also the hyphenation would be Kron-ecker; but it is not. As I also explained there are reasons why people just seeing this (btw very rare) name written might actually – user9072 May 25 '11 at 12:13
up vote 9 down vote accepted

Kron-ecker, I would think, being a native speaker of German. Kron(e) is crown, Ecker alone is a not totally uncommon german name.

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Thank you, Stefan. Unless in the next two days someone provides a more nearly comprehensive list of preferred hyphenations of mathematician's name, I will rate this answer as the "accepted" one. – John Sidles May 24 '11 at 17:25
I politely disagree, for the reasons explained in my answer. – user9072 May 24 '11 at 17:26
At least on on-line German hyphenation service (who knew they existed?) agrees with Stefan in stipulating "Kron-ecker". URL: ''; – John Sidles May 24 '11 at 18:08
John Sidles, since it might get lost in the middle of my answer, as 'Kron-' is undeniably a common prefix in German and for a 'usual' word it is correct even imperative to split of the full prefix, it would not be surprsing that if this happens even if it were incorrect. The problem is that Kronecker is not a word but a name not matching any actual word. – user9072 May 25 '11 at 1:46

Kro - necker since it matches the way the name is pronunced, which is something like KROW nek er , according to and my experience (native speaker German and 10+ years experience in native German math environment).

More generally, I think this prunciation guide could be useful to decide such questions for other names.


I leave my original answer unchanged, as otherwise the comments might not make sense after the edit. I add some more explanation justifying the correctness, at least so I think, of my answer and expand it; however I might actually be the case that both answers are correct, but I am not sure, details below.

A disclaimer: I do not claim any expert knowledge on anything below, but after some reading I hope to get it about right.

First, a general remark: German hyphenation rules were changed somewhat recently; the general trend of this change is a desire for simplification and thus also hyphenation more along the lines of the 'breaks' of the spoken language. (This is not everything there is to it, but I do not want to go into all details; to be honest, I'd also have a hard time doing so.) Still, as pointed out by Theo Buehler, it is/remains true that words that arise as a composition of other words, say two nouns or an added prefix are first to be hyphenated along this structural break and then the composing parts are broken up. Often this is simple as it is clear how the word is build up, but sometimes it is not. If the structure is not clearly visible (anymore) hyphenation along the spoken breaks is at least also correct.

So, now what about Kronecker. It is no doubt true that 'Kron-' is a common prefix (to signal a relation to crown in the real and figurative sense), as documented by words like Kronprinz, Kronjuwelen, Kronleuchter; in all these cases the word without 'Kron' has a clear meaning and the 'Kron' modifies it. (This explains also, I'd say, why an automatic hyphenating program hyphenates there, it knows the prefix.) However, I maintain that this does not mean that Kronecker should be treated like this, or at least it does not have to be treated like this, as it is a name whose origin is at least unclear and the common pronunciation suggestes that the origin is 'forgotten'. I can well imagine that the name originated in this way (as alluded to by Thomas Geschke); note that Acker means field (in the agricultural sense), the plural is Äcker which is essentially homophonic to Ecker. So, Kronecker might well have orginated in the way that a person was refered to the place of residence at/near the Kronacker or Kronäcker (the field(s) of the king). In fact, Kronacker exists also as a name. There might however also be other explanations for the name, though I agree they seem less plausible [Kroh and Krohn, the h is silent, are existing namens too; so Kronecker could also have developped as the Kroh(n) from Necker or Neckar; the latter are geographical names in Germany]; I don't know. All I want to say is that the fact that Kronecker is Kron+ecker is (if it is so at all) at least not clearly visible, and indeed blurred both by the spelling and by the pronunciation. Thus, it is at least admissible so hyphenate along the spoken break that is Kro-necker. It might also be correct to hyphenate Kron-ecker (but I do not know this).

Since we now discussed the first hyphenation point, now for the second though nobody asked for it: Krone-cker This seems to contradict the pronunciation I gave at the start but not entirely so as the ck is a sort-of double k, and pronunciation is actually not far from Kro nek ker. Indeed according to the old hyphenation rules I learned in school one would have hyphenated a word like 'backen' as bak-ken [c becomes k]; yet there might have been an exception for proper names. Yet by the new rules one hyphenates ba-cken. And, in analogy so Krone-cker.

To sum it up: Kro-ne-cker is I believe correct; perhaps also Kron-ecker (perhaps it is even more correct).

So, to answer the equivalent formulation of the question: I would not change the default behavior of LaTeX, as the default is at least also correct.

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Hmmm ... and perhaps I should mention too, that a Google Books search (limited to 1960-present) comparing usages of "Kro-necker" to usages of "Kron-ecker", turns up numerous examples of both, with "Kro-necker" preferred roughly 4-to-1. And yet, perhaps this reflects the dominance of Donald Knuth's hyphenation algorithm rather than lexicographic correctness? – John Sidles May 24 '11 at 17:34
Since when does German orthography have anything to do with pronunciation? There must have been yet another reform I missed. Duden is quite clear on this: "Zusammensetzungen und Wörter mit Präfix trennt man zwischen den einzelnen Bestandteilen.", Duden, Die amtliche Regelung der deutschen Rechtschreibung, §111. To be honest, I'm completely lost since the reform, but this seems a rather clear case. – Theo Buehler May 24 '11 at 17:45
unkown (google) is right, at least when German grammatic rules are assumed. Duden-Regel 164 says hyphenation should follow the pronounciation of the slowly-spoken word, which is "Kro-necker". And even if that's controversial, the rule says that the new line should never begin with a vowel, excluding "Kron-ecker". – Konrad Waldorf May 24 '11 at 17:56
@Konrad: Well, I'm not going to indulge in a further discussion, but if I understand correctly, rule 164 applies to simple words (einfache Wörter). As Stefan argued (and I would) Kronecker should be treated as a composite, no? So rule 167 should be applied, which leads to Stefan's answer. But I'd have no problem to stand corrected. – Theo Buehler May 24 '11 at 18:08
Theo Buehler, yes but I'd say Kronecker is a proper name, and not a composition like 'Haustor' (which thus is hyphenated, and also at least more-or-less pronuced, Haus-tor; and not Hau-stor or Haust-or). Whether the ethymology of the name is the one Stefan Geschke suggest is I think something that would need to be confirmed; after all 'Necker' exists also in Germany. And even if the ethymology would be the one suggested I'd say it is somehow 'lost', because there is no reason not to say Kron-ek-er, which would suggest it, yet which for all I know is not done. – user9072 May 24 '11 at 18:21

Cute question. That said, I think that a good strategy might be that you should not allow any hyphenation of "Kronecker". It would be very confusing for any reader to go along and hear about the Kro-

necker delta matrix, and it would also be confusing to be explained that the Kron-

ecker product of matrices is simply their exterior product.

A better approach is the following. Do not worry about things like line breaks until you have completely completed the draft of the paper. Then, at the end, yes, you should go back through and correct bad breaks by hand. Sometimes this means that you should force LaTeX to fit more or less than it wants to in a line. More often, it means that you should rewrite one sentence somewhere to avoid a bad hyphenation.

When you do submit to a journal, they may impose a house style. But you will have a chance at the end to go over the proofs, and you can at that time do a similar one-word-rewrite to fix bad hyphenation.

(I have marked my answer as Community Wiki because, although I think this question is cute, I don't think it's the type of question for which answers should accrue "reputation points". That said, marking the answer CW has the side effect of inviting edits to the answer. So, just to emphasize: by all means please improve ("wiki") this answer, provided you do not change the basic thrust of the answer; if you wish to disagree, post a different answer.)

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Please do not use sup for that! It sort of kills the semantic web, but, well, that's mostly dead anyways... but it also kills my eyes! – Mariano Suárez-Alvarez May 25 '11 at 2:24
@Mariano: Sorry! I could not figure out how to include a small footnote, but some googling turned up… . You are not the first to complain about the hack: – Theo Johnson-Freyd May 25 '11 at 3:56
@Mariano: Then again, even if this were not CW, there's nothing stopping you (save politeness) from changing the answer. I hereby give you permission to edit the answer as much as you like. – Theo Johnson-Freyd May 25 '11 at 3:58

Kronecker is almost certainly derived from a place name, Kroneck. Krone means crown, and Eck means corner, this ending is frequently used for names of castles. Therefore the hyphenation should definitely be Kron-ecker.

Edit: Apparently a reform in the late 1990s changed the rules. If I understand it correctly, both hyphenations are now permissible.

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This is another good explanation for the ethymologie of the name; possibly the best one. However, could you kindly elaborate why the hyphenation thus should 'definitely' (or why at all) by Kron-ecker. (Perhaps with a reference?) – user9072 May 25 '11 at 8:51

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