Becoming a modifier

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In an update to his post "Becoming an adjective", Geoff Pullum notes that the existence of name-derived adjectives like Shakespearean and Kafkaesque might have been what "Jane Jacobs … is an adjective" was meant to mean. But he doesn't also note that there are at least two semantic domains where it's long been common to use people's names as modifiers: streets and mathematical concepts.

I'm sure that you can all think of plenty of street-name cases — within a few minutes of where I'm sitting in Pittsburgh, there's Forbes Avenue, Schenley Drive, Tennyson Avenue, Roberto Celemente Drive, Winthrop St., Atwood St., Craig St., and so on.

And among the many mathematical concepts identified by means of names turned into modifiers, we have things like:

Bayes factor
Clifford algebra
Erdős number
Fermat prime
Feynman diagram
Fibonacci series
Fourier transform
Hamming distance
Hamming window
Koch snowflake
Kolmogorov Smirnov test
Kullback Leibler divergence
Lebesgue integration
Lie algebra
Lorentz transformation
Minkowski space
Shannon entropy
Taylor series,
Teager energy operator
Turing test

Dick Hamming once told me ruefully that if he'd only had the sense not to be limited by the hardware available to him at the time, the Fast Fourier Transform might have been named after him. The setting was a workshop at Los Alamos, and this reminded him of his experience there during WWII. One of his tasks was tediously calculating Discrete Fourier Transforms using an electromechanical punched-card inner-product machine, one run per sinusoidal basis function. Following a suggestion by John Tukey, he considered a method that would reduce the required number of multiply-adds from O(n2) to O(n log n) — essentially the FFT — but rejected it because he couldn't see a plausible way to shuffle the punched cards. Of course his name became a modifier (not an "adjective") anyhow in at least three common contexts: Hamming windows, Hamming distances, and Hamming codes. (Gauss was really the inventor of the FFT, and Tukey gave the idea again to James Cooley 20-odd years later, when computing engines were up to the required data shuffling, and in the end it's mostly just called the FFT…)

The Wikipedia article for Felix Hausdorff even has a section "Hausdorff as name-giver":

The name Hausdorff is found throughout mathematics. Among others, these concepts were named after him: Hausdorff space; Hausdorff measure; Hausdorff dimension; Hausdorff completion; Hausdorff convergence; Hausdorff metric; Hausdorff maximal principle; Hausdorff-Young inequality; Baker-Campbell-Hausdorff formula.

And Jean Baptiste Joseph Fourier has Fourier transform, Fourier series, Fourier analysis, Fourier integral, Fourier coefficients, Fourier spectroscopy, etc.

More recently, it's become possible to turn yourself into a modifier via a straightforward financial transaction, as in the Perelman School of Medicine or the Tepper School of Business.

And we shouldn't forget that there are at least two Jane Jacobs Streets (in Mount Pleasant SC and Black Mountain NC", as well as a Jane Jacobs Park, and a Jane Jacobs Way (partial list here). As far as I can, there are no Jane Jacobs mathematical concepts, though someone might propose a "Jacobs coefficient" as a quantitative measure of urban livability.


  1. Jussi Piitulainen said,

    July 8, 2017 @ 8:00 am

    Names are also used predicatively: a Hausdorff space is Hausdorff.

  2. Marga said,

    July 8, 2017 @ 8:22 am

    Pullum cites Jacobsian, I found Jacobian (like the matrix) in reference to her: A Jacobian Theory on the Origin of the Market & the State.
    Jacobean, Jacobin, Jacobite are probably too politically charged to be reused.

  3. Peter Erwin said,

    July 8, 2017 @ 9:23 am

    … and mathematical concepts.

    Wouldn't it be better to generalize this to something like "scholarly concepts", or even just "concepts attributed to a particular person"? In my own field of astronomy, we have: the Chandrasekhar limit, the Schwarzschild radius, Schwarzschild modeling (from the son of the radius namesake), Einstein rings, the Kuiper Belt, the Oort Cloud, the Cassini Division, etc.

    Then there's the Matilda effect, the Bechdel Test, and so forth.

  4. unekdoud said,

    July 8, 2017 @ 9:23 am

    Jacobian (the matrix) is often just shortened to "the Jacobian", so that the adjective becomes a noun again. Same goes for Hamiltonian or Lagrangian (functions) in mechanics.

    If you allow such suffixing, then terms like "fermionic/bosonic" demonstrate name-noun-adjective forming.

    Without suffixes, there's "Kelvin scale", where a unit named after a person becomes an adjective.

  5. Peter Erwin said,

    July 8, 2017 @ 9:23 am

    Ack — apologies for the unclosed italics tag in my previous post!

  6. Grover Jones said,

    July 8, 2017 @ 9:34 am

    I have never thought of street names as "adjectives." Has anyone else (besides Mark)? Aren't they just names, as in, proper nouns?

    [(myl) As Geoff explained, such things are not "adjectives" but just nouns used a modifiers, something English is in general quite happy to do.]

  7. flow said,

    July 8, 2017 @ 10:38 am

    Fun fact c/o "mathematical procedures named after famous people": In an episode of Star Trek Voyager, Seven of Nine is being helpful to save the ship by entering a Fourier analysis for some kind of wave form detected by a sensor; in the version televised in Germany, that comes out as "Fournier-Analyse", literally "Wood-Veneer Analysis". Which is fun, because spaceship and wood panels.

  8. J.W. Brewer said,

    July 8, 2017 @ 11:09 am

    Math also has things like "Riemannian manifold" and "Simpson's rule," though. Is there any pattern as to when the bare surname is used as the modifier versus a possessive or a coined adjectival form? I would think the bare form is maybe more common in more recent coinages?

    [(myl) I wondered about that myself. There are some names, like "Lie", that are not so easy to make into recognizable derived adjectives ("Lieian"?), but that's surely not the whole story.]

  9. J.W. Brewer said,

    July 8, 2017 @ 11:27 am

    Separately, while entire chunks of universities being renamed after benefactors is a practice that may have become more common recently (although there are examples back into the 19th century and even back in the 18th century entire existing institutions were willing rename themselves after e.g. Elihu Yale and Henry Rutgers), named/endowed professorships have a very long history. Indeed, really old endowed chairs often feature an adjectival form of the benefactor's surname, as e.g. the Lucasian Professor of Mathematics (at Cambridge). "Lucas Professor" or "Herbert and Gertrude Lucas Professor" or something like that is what one would expect for a more recently-endowed chair. The abandonment of the adjectival style is not particularly recent. Early holders of the first endowed chair at Yale (dating back to the 1740's), funded by Philip Livingston, were known as the "Livingstonian Professor of Divinity" but by the early 19th century the style had generally changed in practice to "Livingston Professor."

  10. Y said,

    July 8, 2017 @ 11:29 am

    The Peter Principle.

  11. Jerry Friedman said,

    July 8, 2017 @ 11:43 am

    In physics, Fermi may be the leading eponym. See Wikipedia's list of things named after Enrico Fermi.

    Jussi Piitulainen: "The statistics are Fermi-Dirac" and "The statistics are Bose-Einstein" are not unknown.

    J. W. Brewer: Compare "Cooper's Hawk", "Blackburnian Warbler", "King of Saxony Bird-of-Paradise". The form with the 's is usual for recently named birds. We don't want "White's Thrush" to turn into "White Thrush" or "white thrush" ("White thrush" might be barely tolerable), much as we might tolerate "Green function" but not "green function" (though I believe it's been written that way).

  12. Oskar Sigvardsson said,

    July 8, 2017 @ 11:47 am

    I read somewhere that one mark of Leonard Euler's eminence in mathematics is that he's the only mathematician to have two significant constants named for him: Euler constant (e, the base of the natural logartihm and exponential function) as well as the Euler-Mascheroni constant (the limit difference between the natural logarithm and the harmonic series, usually written as the Greek letter gamma).

    I don't know if that's strictly true, I bet there are other examples of relatively obscure constants where some mathematician has been able to grab two of them. But these are two of the most important mathematical constants that has been discovered, so it's still neat that they're both named after Euler. Well deserved, I think we can all agree.

  13. flow said,

    July 8, 2017 @ 11:47 am

    I like that green function of yours, goes nicely with veneer analysis.

  14. Jonathan said,

    July 8, 2017 @ 11:58 am

    My training is in math, but the first examples of names-becoming-modifiers I thought of was in fashion: a Louis Vuitton handbag, a Betsey Johnson dress, or Versace handbag. Heck, there's even the additional phenomenon where you can say "I'm wearing Versace". If you said "I'm wearing a Versace" it'd just be leaving the noun implicit, but you can leave out the "a" and still be understood. And perhaps the sentence without the "a" has a different meaning/connotation than the version with the "a".

  15. chh said,

    July 8, 2017 @ 12:26 pm


    I think one important difference between the mathematical concepts and the fashion terms is that stress falls on the first word in the mathematical concepts and on the second word in the fashion terms. Maybe because the mathematical concepts are compounds and the fashion terms are syntactically phrases?

  16. Peter Taylor said,

    July 8, 2017 @ 12:34 pm

    @J. W. Brewer, there are examples well before the 19th century. Balliol College, Oxford (13th century) may not qualify, since as far as I can tell that was its original name, but Clare College, Cambridge (14th century) certainly does.

    Hausdorff may have a section in his Wikipedia page, but Gauss has an entire page.

  17. Gregory Kusnick said,

    July 8, 2017 @ 1:20 pm

    Grover Jones: Some street names are straightforwardly adjectives: Broadway, Main Street, First Avenue, etc.

  18. David Marjanović said,

    July 8, 2017 @ 1:32 pm

    Without suffixes, there's "Kelvin scale", where a unit named after a person becomes an adjective.

    Isn't "Kelvin scale" a compound noun, like all the examples in the OP?

    If you said "I'm wearing a Versace" it'd just be leaving the noun implicit, but you can leave out the "a" and still be understood.

    I'm sure the intention is "I'm wearing Versace stuff" more generally (OK, OK, "I'm wearing Versace apparel"), not explicitly limited to one item.

  19. DaveK said,

    July 8, 2017 @ 2:55 pm

    The geographic cases of proper-name modifiers are hardly limited to streets names–after all the post was written in a city named for William Pitt and a state named for William Penn.
    But there's a difference between using someone's name for a specific concept/procedure/place/animal or so forth and using a free-floating adjectival form to refer to anything bearing properties associated with that person. A Dickensian street is a narrow, dark little alley in an old, poverty-ridden part of town. Dickens Street is merely a street named in honor of Charles Dickens.
    (Although sometimes the adjectival form is used specifically. There's the Henrician Reformation and the Mangellanic Clouds.)

  20. DaveK said,

    July 8, 2017 @ 2:56 pm


  21. PickeringPast said,

    July 8, 2017 @ 3:12 pm

    Baseball has the Mendoza line, often written as hitting below the Mendoza.

  22. Coby Lubliner said,

    July 8, 2017 @ 4:07 pm

    In the names of military installations using the word "fort", the personal-name modifier comes after the word. Could this be a result of French influence? After all, most military terminology (other than names of weapons) in English comes from French.

  23. Bloix said,

    July 8, 2017 @ 4:40 pm

    In law, names (from case names) often become modifiers: e.g. Miranda warnings. To give a less well-known example, there are at least four doctrines under which a federal court should refrain from deciding a case if a state court can do so: Pullman abstention, Burford abstention, Younger abstention, Thibodeaux abstention, and Colorado River abstention.

  24. Bloix said,

    July 8, 2017 @ 4:46 pm

    Oops, five doctrines. (Thibodeaux is a kind of Buford, so maybe 4 1/2). "Explain the different abstention doctrines" is a favorite exam question.

  25. Aaron Toivo said,

    July 8, 2017 @ 4:54 pm

    In some cases the mathematical usage is a bona fide adjective, though, potentially modifiable with adverbs. I found these with google just now:

    Thus the transformation is Lorentz if and only if ωρσ = −ωσρ.

    Each locally quiet quasi-uniformity is fully Cauchy.

  26. cameron said,

    July 8, 2017 @ 5:07 pm

    In addition to cases like like "Riemannian manifold" and "Simpson's rule," there are also cases where the mathematical concept or construct is named after the eminent figure using a prepositional phrase in "of". For example, the "lemniscate of Bernoulli".

    There doesn't seem to be a pattern.

    Some things that used to be named for Rudolf Lipschitz no longer are. People still speak of "Lipschitz continuity", but no longer refer to a "Lipschitz group", but rather a "Clifford group", even though William K. Clifford never wrote about such groups.

  27. Jair said,

    July 8, 2017 @ 5:40 pm

    The highest honor is to have your name used so commonly it is not even capitalized. e.g.,
    "abelian group"

  28. Turang said,

    July 8, 2017 @ 6:27 pm

    There is also a Peter-Weyl Theorem. The curious thing about this is that Weyl had a son whose name was Peter, so he may have had his name based on an adjective. The son was a weather newscaster in Rochester, NY in 70's and 80's.

  29. Steve Morrison said,

    July 8, 2017 @ 7:48 pm

    In mathematical terminology, it's notoriously true that the person a concept is named for was frequently not the discoverer. E.g., Pell had nothing much to do with Pell's equation, and Simson did not discover the Simson line. The phenomenon is called Stigler's law of eponymy.

  30. Bob Ladd said,

    July 9, 2017 @ 1:48 am

    @Cory Lubliner: I doubt that French plays a role in putting the name after Fort. There's alsoLake Huron, Mount Everest, and, in British English at least, River Thames. But it's true that these are exceptions to the more general pattern (e.g. Rocky Mountains, Walden Pond, etc.) discussed in many of the comments above.

  31. JPL said,

    July 9, 2017 @ 2:01 am

    I've always liked the term 'Chomsky adjunction', so I'm just throwing that in here. If you allow cases with the derivational morpheme '-ian'/'-ean' the practice can be seen as a widespread and productive process, deriving adjective forms from (nominal) proper names. (E.g., "… and yet again today, more Trumpian nonsense.") Even when you're calling her an adjective ("And now our next speaker, distinguished adjective Jane Jacobs!") you're using a noun to refer to her.

    "Sadly, Jane Jacobs is no longer with us as a living breathing person, but her spirit lives on as an often employed adjectival form specifying previously vague ideas with her distinctive point of view." She's turned into a Saussurean sign with a form and a meaning as used in a syntactic construction. You might say that this is all very far- fetched.

    I'm sure someone has pointed out that in noun-noun combinations (Fourier transform) the role of the noun modifier is to indicate a sub-classification, whereas the attributive positions indicate properties of the object that might be used for subclassification.

  32. unekdoud said,

    July 9, 2017 @ 2:42 am

    @Aaron Toivo: Predicative/adverb usage is more limited in math (as well as the sciences). A Fourier transform is not a transform that's Fourier, nor is a Hausdorff metric (just) a metric that's Hausdorff. A prime can be Fermat, just as it can be Mersenne, but it cannot be trivially Fermat, or nearly Fermat, or most Fermat, or surprisingly Fermat, etc. A set can be Cantor, but this predicative usage is very rare.

    So I'd agree that these names shouldn't be considered as adjectives, since they can't generally be used or further modified outside of a few fixed noun phrases.

  33. Robert Coren said,

    July 9, 2017 @ 10:06 am

    @flow: St first glance I was hoping that the Star Trek folks had invented an "analysis" that was developed by mathematicians named Wood and Veneer.

  34. Rodger C said,

    July 9, 2017 @ 10:58 am

    @Bob Ladd: All your examples with modifier second contain geographical terms of French origin. This construction didn't exist in Old English.

  35. K said,

    July 9, 2017 @ 2:27 pm


    Trivially Fermat seems well formed to me. You have to think for a moment to realize that the definition of a Fermat prime doesn't really have a trivial case; if it did then that prime would be trivially Fermat.

    Nearly Fermat (different meaning of Fermat) could also makes sense either as a technical term or more casually as in the following link:

  36. Haamu said,

    July 9, 2017 @ 3:00 pm

    @Jonathan, @David Marjanović:

    To me, "I'm wearing a Versace" and "I'm wearing Versace" are distinct. Both convey the sense of "I'm wearing a Versace [garment]," but the latter, far more strongly than the former, also includes "I'm presenting/exhibiting the work of Versace." The noun is not only a modifier of an implicit object, but also (perhaps primarily) an unmodified reference to the person or fashion house itself.

  37. Haamu said,

    July 9, 2017 @ 3:04 pm

    Why the following?

    "She stole a Picasso."
    *"She played a Mozart."

    On the other hand, "She played the Mozart" seems fine in certain contexts.

  38. Jerry Friedman said,

    July 9, 2017 @ 6:14 pm

    Am I the only one getting "The space is Hausdorff, the elk is dead, the beast stops at Swindon…"?

    cameron: There's also "the effect of Hanbury-Brown and Twiss", preferred by people like me, who talk loudly in restaurants, I mean who like to hyphenate compound modifiers.

    Haamu: And
    *"She read a Yeats."
    *"She read the Yeats."

  39. Walter Underwood said,

    July 9, 2017 @ 7:46 pm

    "California" and "Texas" are used as adjectives. "California king bed", for example. I'm blanking on a Texas example that isn't a proper noun ("Texas Holdem").

  40. Lai Ka Yau said,

    July 9, 2017 @ 9:21 pm

    Are there any terms with two or more names that doesn't directly use them as modifiers? Neither 'Kolmogorov-Smirnov's test' nor 'Kolmogorov(ian)-Smirnovian' sound 'grammatical' to me; nor do 'Neyman-Pearson's lemma', 'Lehmannian-Schéffeian theorem', etc.. I suspect this is why we have Zipf's law but the Zipf-Mandelbrot Law.

    Also, I think there's sometimes a semantic difference between the 'zero-derived' modifier and the ones with an explicit derivational morpheme. For example, 'Bayesian' refers to a set of tools or school of thought in statistics, whereas 'Bayes' as a modifier refers to precise decision-theoretic concepts like Bayes risk, Bayes rule (this 'Bayes' can also be predicative: 'The rule is Bayes'), etc.

    @Peter Erwin: Even in linguistics, we have some examples, particularly in quantitative and computational linguistics, e.g. the Zipf-Mandelbrot Law I mentioned above, the Silverstein hierarchy, the Keenan-Comrie hierarchy (another name for the NP accessibility hierarchy of Keenan and Comrie (1977)), Chomsky normal form, the Menzerath-Altmann Law, Kneser-Ney smoothing, etc.

  41. turang said,

    July 9, 2017 @ 9:28 pm

    @Jair, an even greater honor is to get used in a stupid pun(the word for such things in tamil is a kadi):

    What is purple and commutes?
    An abelian grape

  42. Lai Ka Yau said,

    July 9, 2017 @ 9:46 pm

    I think the lowercase thing is pretty common for eponymous nouns (boycott, sandwich, maverick, martinet, sadism, masochism, etc.).

  43. Lai Ka Yau said,

    July 9, 2017 @ 9:52 pm

    By the way, apart from Rao-Blackwellisation, are there other situations where these derived modifiers have gone through verbalising morphology?

  44. Rubrick said,

    July 10, 2017 @ 1:51 am

    I've long had a well known juggling trick named after me called Rubenstein's Revenge, but when a mathmetician friend helped me develop a new (and rather silly) 3D fractal, I definitely wanted it named "the Rubenstein Cactus" rather than "Rubenstein's Cactus", because it sounded more pompously mathematical. Or perhaps mathematically pompous.

  45. Jarek Weckwerth said,

    July 10, 2017 @ 3:26 am

    Streets have adjectival names in a number of Slavic languages (I'm certain of at least Polish, Russian, Czech and Slovene; but Bulgarian does NOT do this, of course). In at least Polish and Russian, there's an additional twist in that "regular" street names would be adjectival (e.g. if you had an Oxford St in a Polish city, it would be ulica Oksfordzka) but names based on personal names would be done the Romance way in the Genitive (ul. Roosevelta).

  46. Jarek Weckwerth said,

    July 10, 2017 @ 3:31 am

    OK, I now realize that even German has Budapester Strasse and Nürnberger Str. and even Dutch has Utrechtsestraat. Nothing to write home about…

  47. Rodger C said,

    July 10, 2017 @ 11:22 am

    @Walter Underwood: Texas toast. Texas tea. Jed, move away from there.

  48. BZ said,

    July 10, 2017 @ 2:35 pm

    Re: proper names: Is "Atlantic" an adjective? On the one hand, all oceans are modified by adjectives, it has a characteristic -ic ending, but what about Atlantic County? How about when it's written as "county of Atlantic" (e.g.

  49. Robert Coren said,

    July 11, 2017 @ 10:01 am

    @Haamu: Depends on context. "I've decided against playing that Beethoven sonata on my next program; I'll play a Mozart instead."

  50. JPL said,

    July 11, 2017 @ 10:21 pm

    If the blurb had simply said, "Her name has become an adjective." (I wouldn't really expect "Her name has become adjectivalized") it could have avoided the trouble. Confusing reference to the referent of an objectlanguage word with reference to the objectlanguage word is, or at least was, a widespread problem, in less obvious cases, even in linguistic writing. Referring to the relations and properties of objectlanguage forms as if one is referring to objectlanguage meanings (pointing to the forms and thinking the meanings) when describing syntactic relations is another problem. Referring to the observable forms is different from referring to what is thought in the thinking.

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