What? You'd call that point a "vertex"??

[Paul Epstein]

While looking at my 16 year old niece's maths exam papers (as you do), I was
struck that the word "vertex" was used to describe the extremum of a parabola.
I was suspicious of this usage because it seemed totally unrelated to
all other uses of "vertex" in mathematics. It isn't a point in a graph, and it isn't
the intersection of two straight lines.
However, when I googled, I found that there is apparently a separate definition
of "vertex" that means "extremum" and applies to parabolas only.
I find it very weird that someone apparently decided to wildly change the usual
meaning of the word "vertex" and apply this new meaning to parabolas only,
when a perfectly good word, "extremum", already exists for the concept.

Who could Adam and Eve it?

Paul Epstein

[Jerry Friedman]

Well, that meaning of the term isn't quite as old as Adam and Eve. (And yes,
I got the rhyming slang.)

"Vertex" also means the top of the head, by the way. I'm not sure at
all that the meaning relating to angles is the oldest in Latin.

--
Jerry Friedman

[Peter T. Daniels]

On Monday, May 22, 2023 at 12:21:37 PM UTC-4, Paul Epstein wrote:

> While looking at my 16 year old niece's maths exam papers (as you do),

No, why would I look at your niece's geometry test? Isn't it "as one does"
Over There, too?

[Silvano]

Jerry Friedman hat am 22.05.2023 um 18:24 geschrieben:

> "Vertex" also means the top of the head, by the way. I'm not sure at
> all that the meaning relating to angles is the oldest in Latin.

JFTR, the Italian PM recently attended a meeting in Hiroshima we
Italians call "vertice dei G7". Where could the Italian "vertice" come from?

BTW, the Italian Wikipedia tells me that Italian "parabole" also have a
"vertice". The figure shown there is the same as
<https://en.wikipedia.org/wiki/Parabola#/media/File:Parts_of_Parabola.svg>.

[bruce bowser]

Oldest compared to what frame of reference?

[TonyCooper]

On Mon, 22 May 2023 09:45:06 -0700 (PDT), "Peter T. Daniels"
<gram...@verizon.net> wrote:

>On Monday, May 22, 2023 at 12:21:37?PM UTC-4, Paul Epstein wrote:
>
>> While looking at my 16 year old niece's maths exam papers (as you do),
>
>No, why would I look at your niece's geometry test? Isn't it "as one does"
>Over There, too?

I find "as you do" in Paul's context very unremarkable with the
meaning "as everyone might". The phrase "as one does" is equally
unremarkable, but it's not at all standard Over Here.

--

Tony Cooper - Orlando,Florida

[Peter T. Daniels]

A lot more "standard" (not that anyone mentioned "standard") than
"as you do."

[Jerry Friedman]

On Monday, May 22, 2023 at 11:51:57 AM UTC-6, Silvano wrote:
> Jerry Friedman hat am 22.05.2023 um 18:24 geschrieben:
> > "Vertex" also means the top of the head, by the way. I'm not sure at
> > all that the meaning relating to angles is the oldest in Latin.

> JFTR, the Italian PM recently attended a meeting in Hiroshima we
> Italians call "vertice dei G7".

...

English "summit". Does Italian "vertice" mean the top of a mountain?

--
Jerry Friedman

[TonyCooper]

On Mon, 22 May 2023 12:19:55 -0700 (PDT), "Peter T. Daniels"
<gram...@verizon.net> wrote:

When you state "Isn't it "as one does" Over There too?" the only way
to interpret the remark is that "as one does" is what is standard Over
Here. The "too" means "as we do".

This seems to be another case of as you say it/write it, then anything
else is somehow questionable or wrong.

[Jerry Friedman]

OK, now I'm sure. The AHD says the etymology is

"Latin, whirlpool, crown of the head (where the hair forms a whorl), vertex,
from /vertere/, to turn; see *wer-2* in the Appendix of Indo-European roots."

"Vortex" is a variant of "vertex".

--
Jerry Friedman

[Silvano]

Jerry Friedman hat am 22.05.2023 um 21:45 geschrieben:

> On Monday, May 22, 2023 at 11:51:57 AM UTC-6, Silvano wrote:
>> Jerry Friedman hat am 22.05.2023 um 18:24 geschrieben:
>>> "Vertex" also means the top of the head, by the way. I'm not sure at
>>> all that the meaning relating to angles is the oldest in Latin.
>
>> JFTR, the Italian PM recently attended a meeting in Hiroshima we
>> Italians call "vertice dei G7".
> ...
>
> English "summit".

I know. My English is not SO bad.

Does Italian "vertice" mean the top of a mountain?

Yes, but not only that. If you can read and understand Italian
<https://www.treccani.it/vocabolario/vertice>

[Paul Wolff]

On Mon, 22 May 2023, at 09:24:39, Jerry Friedman posted:
>On Monday, May 22, 2023 at 10:21:370 >> While looking at my 16 year old niece's maths exam papers (as you do), I was

Nor I, but vertex to an educated Roman also meant whirlpool or eddy or
something else of that kind. And then there's fastigium, which seems to
have a kind of vertex-like meaning too.
--
Paul W

[Peter Moylan]

On 23/05/23 03:15, Stefan Ram wrote:

> Paul Epstein <peps...@gmail.com> writes:
>> the word "vertex" was used to describe the extremum of a parabola
>

> |vertex, n. ... |1. a. ... |the point in a curve or surface at which
> the axis meets it ... |1715 J. T. Desaguliers tr. N. Gauger Fires
> Improv'd 13 |Two half Parabolas's whose Vertex's are C c.

That's very confusing. A parabola meets the vertical axis at one point,
and the horizontal axis at two points. (Or sometimes none, and rarely
one.) Usually none of those three points is at the extremum of the
parabola.

Ah. Google now tells me that the axis in question is the line of
symmetry of the parabola. Fair enough, but the word "axis" tout court is
highly ambiguous.

Until this thread I had never heard of the vertex of a parabola, and
parabolae were certainly covered in my Form 3 mathematics. Is this a
recently introduced term?

One traditional definition of a parabola is in terms of a slice taken
through a cone. In the case of a parabola, that slice /never/ goes
through the vertex of the cone.

--
Peter Moylan Newcastle, NSW http://www.pmoylan.org

[lar3ryca]

Strange. I could understand 'vortex' for a whirlpool.

--
What do you call a fish without an eye?
Fsh.

[Mark Brader]

Paul Epstein:

> While looking at my 16 year old niece's maths exam papers (as you do), I was
> struck that the word "vertex" was used to describe the extremum of a parabola.
> I was suspicious of this usage because it seemed totally unrelated to

> all other uses of "vertex" in mathematics...

The vertex of a parabola is the point where its curvature is greatest,
just like a vertex of a polygon.
--
Mark Brader | "One must scythe the thickets of metaphor
Toronto | if one wishes to harvest the grain of reason."
m...@vex.net | --Robert Ludlum

[Jerry Friedman]

On Monday, May 22, 2023 at 8:20:57 PM UTC-6, Peter Moylan wrote:
> On 23/05/23 03:15, Stefan Ram wrote:
> > Paul Epstein <peps...@gmail.com> writes:
> >> the word "vertex" was used to describe the extremum of a parabola
> >
> > |vertex, n. ... |1. a. ... |the point in a curve or surface at which
> > the axis meets it ... |1715 J. T. Desaguliers tr. N. Gauger Fires
> > Improv'd 13 |Two half Parabolas's whose Vertex's are C c.
>
> That's very confusing. A parabola meets the vertical axis at one point,
> and the horizontal axis at two points. (Or sometimes none, and rarely
> one.) Usually none of those three points is at the extremum of the
> parabola.
>
> Ah. Google now tells me that the axis in question is the line of
> symmetry of the parabola. Fair enough, but the word "axis" tout court is
> highly ambiguous.
>
> Until this thread I had never heard of the vertex of a parabola, and
> parabolae were certainly covered in my Form 3 mathematics. Is this a
> recently introduced term?

...

Stefan Ram gave the 1715 quotation from the OED. "Vertex" is the
only term I know for that point. What did you call it? (Also, "axis" is
the term I know for the line of symmetry.)

--
Jerry Friedman

[Jerry Friedman]

On Monday, May 22, 2023 at 9:10:16 PM UTC-6, lar3ryca wrote:
> On 2023-05-22 16:16, Paul Wolff wrote:
> > On Mon, 22 May 2023, at 09:24:39, Jerry Friedman posted:
> >> On Monday, May 22, 2023 at 10:21:370 >> While looking at my 16 year
> >> old niece's maths exam papers (as you do), I was
> >>> struck that the word "vertex" was used to describe the extremum of a
> >>> parabola.
> >>> I was suspicious of this usage because it seemed totally unrelated to
> >>> all other uses of "vertex" in mathematics. It isn't a point in a
> >>> graph, and it isn't
> >>> the intersection of two straight lines.
> >>> However, when I googled, I found that there is apparently a separate
> >>> definition
> >>> of "vertex" that means "extremum" and applies to parabolas only.
> >>> I find it very weird that someone apparently decided to wildly change
> >>> the usual
> >>> meaning of the word "vertex" and apply this new meaning to parabolas
> >>> only,
> >>> when a perfectly good word, "extremum", already exists for the concept.
> >>>
> >>> Who could Adam and Eve it?
> >>
> >> Well, that meaning of the term isn't quite as old as Adam and Eve.

...

> >> "Vertex" also means the top of the head, by the way. I'm not sure at
> >> all that the meaning relating to angles is the oldest in Latin.
> >>
> > Nor I, but vertex to an educated Roman also meant whirlpool or eddy or
> > something else of that kind. And then there's fastigium, which seems to
> > have a kind of vertex-like meaning too.

> Strange. I could understand 'vortex' for a whirlpool.

Maybe now you've seen my post that says "vortex" was a Latin variant of

[Paul Epstein]

Thanks. That's exactly the type of information I was looking for.
Do you know where I can verify this info?
I haven't been able to google my way to a clear account and definition of
curvature, particularly in the case of a polygon, where the vertices don't have derivatives.

Paul Epstein

[Peter Moylan]

On 23/05/23 21:30, Jerry Friedman wrote:
> On Monday, May 22, 2023 at 8:20:57 PM UTC-6, Peter Moylan wrote:
>> On 23/05/23 03:15, Stefan Ram wrote:
>>> Paul Epstein <peps...@gmail.com> writes:
>>>> the word "vertex" was used to describe the extremum of a
>>>> parabola
>>>
>>> |vertex, n. ... |1. a. ... |the point in a curve or surface at
>>> which the axis meets it ... |1715 J. T. Desaguliers tr. N. Gauger
>>> Fires Improv'd 13 |Two half Parabolas's whose Vertex's are C c.
>>
>> That's very confusing. A parabola meets the vertical axis at one
>> point, and the horizontal axis at two points. (Or sometimes none,
>> and rarely one.) Usually none of those three points is at the
>> extremum of the parabola.
>>
>> Ah. Google now tells me that the axis in question is the line of
>> symmetry of the parabola. Fair enough, but the word "axis" tout
>> court is highly ambiguous.
>>
>> Until this thread I had never heard of the vertex of a parabola,
>> and parabolae were certainly covered in my Form 3 mathematics. Is
>> this a recently introduced term?
> ...
>
> Stefan Ram gave the 1715 quotation from the OED.

I noticed that, but somehow failed to notice that that rules out
"recently introduced". Blame an ageing brain.

> "Vertex" is the only term I know for that point. What did you call
> it? (Also, "axis" is the term I know for the line of symmetry.)

I don't think we had names for these things, other than minimum and
maximum. I can see that "line of symmetry" would be a useful term for
the case where that line is tilted with respect to one's coordinate
axes, but we never covered that case in high school, and beyond high
school the topic hardly ever came up, except for parabolic antennae.

The equation describing a parabola did come up, of course, for example
in least-squares fitting of data to a quadratic [1], but in that sort of
application one uses ad hoc terminology.

[1] That very topic arose in a job I did a few years ago. Given data for
sound intensity versus angle, the customer wanted a way to express this
as a sum of two or three sound sources at unknown angles. I decided to
tackle this by fitting the data to a sum of five Gaussian functions. How
this is related to quadratic least squares is left as an exercise for
the reader.

A few years earlier, I was asked to produce a real-time calculation
method for gas concentration versus detector output, for a carbon
monoxide detector, based on calibration data at a few fixed points. In
that case, though, I ended up deciding that least squares approximation
by a cubic was a better solution, with the actual cubic changing over
the range. My boss originally asked for a spline solution, but I was
able to convince him that for that application area splines were not the
best approach.

[Dingbat]

On Monday, May 22, 2023 at 9:51:37 PM UTC+5:30, Paul Epstein wrote:
> While looking at my 16 year old niece's maths exam papers (as you do), I was
> struck that the word "vertex" was used to describe the extremum of a parabola.
> I was suspicious of this usage because it seemed totally unrelated to
> all other uses of "vertex" in mathematics. It isn't a point in a graph, and it isn't
> the intersection of two straight lines.
> However, when I googled, I found that there is apparently a separate definition
> of "vertex" that means "extremum" and applies to parabolas only.
>

How curious!

>
> I find it very weird that someone apparently decided to wildly change the usual
> meaning of the word "vertex" and apply this new meaning to parabolas only,
> when a perfectly good word, "extremum", already exists for the concept.
>

Graph theoreticians found a new use for VERTEX. Try this search:
<https://www.google.com/search?q=graph+vertex+edge>

>
> Who could Adam and Eve it?

>:
Cockney rhyming slang, this says:
<https://www.phrases.org.uk/idioms/would-you-adam-and-eve-it.html>
1) Where's the rhyme?
2) Is it everyone's idiom now?

[Jerry Friedman]

On Tuesday, May 23, 2023 at 6:19:57 AM UTC-6, Paul Epstein wrote:
> On Tuesday, May 23, 2023 at 6:43:51 AM UTC+1, Mark Brader wrote:
> > Paul Epstein:
> > > While looking at my 16 year old niece's maths exam papers (as you do), I was
> > > struck that the word "vertex" was used to describe the extremum of a parabola.
> > > I was suspicious of this usage because it seemed totally unrelated to
> > > all other uses of "vertex" in mathematics...
> >
> > The vertex of a parabola is the point where its curvature is greatest,
> > just like a vertex of a polygon.

> Thanks. That's exactly the type of information I was looking for.
> Do you know where I can verify this info?
> I haven't been able to google my way to a clear account and definition of
> curvature, particularly in the case of a polygon, where the vertices don't have derivatives.

Not to speak for Mark--OK, this may look a lot like speaking for Mark.
You can see the usual definition of curvature of a plane curve in terms
of derivatives in the numbered equations at

https://mathworld.wolfram.com/Curvature.html

See especially equations 13-15.

Intuitively, though, the curvature is 0 anywhere within a line segment and
infinite at the vertex of an angle, which I think is what Mark meant.

But the etymological connection is not through curvature but through
the meaning of "top of the head, highest point".

--
Jerry Friedman

[Jerry Friedman]

On Monday, May 22, 2023 at 3:13:21 PM UTC-6, Silvano wrote:
> Jerry Friedman hat am 22.05.2023 um 21:45 geschrieben:
> > On Monday, May 22, 2023 at 11:51:57 AM UTC-6, Silvano wrote:
> >> Jerry Friedman hat am 22.05.2023 um 18:24 geschrieben:
> >>> "Vertex" also means the top of the head, by the way. I'm not sure at
> >>> all that the meaning relating to angles is the oldest in Latin.
> >
> >> JFTR, the Italian PM recently attended a meeting in Hiroshima we
> >> Italians call "vertice dei G7".
> > ...
> >
> > English "summit".

> I know. My English is not SO bad.

Sorry, just making the connection to my question obvious to all.

> > Does Italian "vertice" mean the top of a mountain?

> Yes, but not only that. If you can read and understand Italian
> <https://www.treccani.it/vocabolario/vertice>

I can understand that well enough to get the general idea.

I see that in differential geometry, "vertice" means a point where
the curvature has a minimum or maximum, (or in general where
the first derivative of the curvature is 0), which led me to find
that English "vertex" has the same meaning. There's a theorem
that every smooth closed curve in the plane has at least four
vertices. For an ellipse, the two maxima and two minima are at
the intersections with the major and the minor axis respectively.

--
Jerry Friedman

[Jerry Friedman]

On Tuesday, May 23, 2023 at 7:01:52 AM UTC-6, Dingbat wrote:
> On Monday, May 22, 2023 at 9:51:37 PM UTC+5:30, Paul Epstein wrote:

...

> > Who could Adam and Eve it?
> >:
> Cockney rhyming slang, this says:
> <https://www.phrases.org.uk/idioms/would-you-adam-and-eve-it.html>
> 1) Where's the rhyme?

With the definition it gave.

> 2) Is it everyone's idiom now?

I've never heard it.

I was interested to see that they listed it with "would you". Does that mean
one can't replace other uses of "believe" with "Adam and Eve"? "Well, I
Adam and Eve it"? "I don't think they Adam and Eved me"?

--
Jerry Friedman

[Sam Plusnet]

On 22-May-23 23:16, Paul Wolff wrote:
> On Mon, 22 May 2023, at 09:24:39, Jerry Friedman posted:

>> "Vertex" also means the top of the head, by the way.  I'm not sure at
>> all that the meaning relating to angles is the oldest in Latin.
>>
> Nor I, but vertex to an educated Roman also meant whirlpool or eddy or
> something else of that kind. And then there's fastigium, which seems to
> have a kind of vertex-like meaning too.

Thank you.
I shall in future refer to the top of my head as "Charybdis".


--
Sam Plusnet

[Jerry Friedman]

That's very Scylly of you.

--
Jerry Friedman

[Sam Plusnet]

What a monstrous claim!

(I lack the hair required to make that 'whirl' atop my head.)

--
Sam Plusnet

[Sam Plusnet]

At one time?
Maybe one could - but it has pretty much fossilised into just that one
exclamation:

"Well! Would you Adam and Eve it!"

An equivalent I haven't heard for a few years is:

"Well! I'll go to the foot of our stairs!"

Sheer nonsense, but it served its purpose.

--
Sam Plusnet

[Paul Epstein]

On Tuesday, May 23, 2023 at 8:43:41 PM UTC+1, Jerry Friedman wrote:
> On Tuesday, May 23, 2023 at 7:01:52 AM UTC-6, Dingbat wrote:
> > On Monday, May 22, 2023 at 9:51:37 PM UTC+5:30, Paul Epstein wrote:
> ...
> > > Who could Adam and Eve it?
> > >:
> > Cockney rhyming slang, this says:
> > <https://www.phrases.org.uk/idioms/would-you-adam-and-eve-it.html>
> > 1) Where's the rhyme?
> With the definition it gave.
> > 2) Is it everyone's idiom now?
> I've never heard it.

The fact that googling the phrase turns up somewhat few references suggests
(to me) that the phrase isn't particularly common.
That surprised me a bit because I'm very familiar with it. Maybe I heard it only
once but it stuck with me.
Or should I say "it stuck with the deep blue sea"?

Paul Epstein

[Kerr-Mudd, John]

That's one for Davy Jones, IMO.
--
Bah, and indeed Humbug.

[J. J. Lodder]

It does, as a degenrate case.
The degenerate parabola is an infinite straight line,
-with a point on it- ,
so the name 'vertex' for it is quite appropriate,

Jan

[J. J. Lodder]

Dingbat <ranjit_...@yahoo.com> wrote:

> On Monday, May 22, 2023 at 9:51:37?PM UTC+5:30, Paul Epstein wrote:
> > While looking at my 16 year old niece's maths exam papers (as you do), I
> > was struck that the word "vertex" was used to describe the extremum of a
> > parabola. I was suspicious of this usage because it seemed totally
> > unrelated to all other uses of "vertex" in mathematics. It isn't a point
> > in a graph, and it isn't the intersection of two straight lines.
> > However, when I googled, I found that there is apparently a separate
> > definition of "vertex" that means "extremum" and applies to parabolas
> > only.
> >
> How curious!
> >
> > I find it very weird that someone apparently decided to wildly change
> > the usual meaning of the word "vertex" and apply this new meaning to
> > parabolas only, when a perfectly good word, "extremum", already exists
> > for the concept.
> >
> Graph theoreticians found a new use for VERTEX. Try this search:
> <https://www.google.com/search?q=graph+vertex+edge>

Not that new. A polygon is just a particular kind of graph,
so it is a natural generalisation,

Jan

[Jerry Friedman]

Actually, if you define a parabola as a slice taken through a cone,
the degenerate case (where the slice goes through the vertex of the
cone) is an angle whose vertex corresponds to the vertex of the
parabola. I couldn't guess, though, whether "vertex" was applied
to parabolas because of that or straight from Latin "high point" or
both.

--
Jerry Friedman

[Adam Funk]

"A Descent into the Vertex" doesn't have the same ring to it.


--
Just memorize these shell commands and type them to sync up. If you
get errors, save your work elsewhere, delete the project, and download
a fresh copy. <https://xkcd.com/1597/>

[Jerry Friedman]

Never mind. I was confused. Yes, that degenerate parabola is a
straight line.

--
Jerry Friedman

[J. J. Lodder]

Sam Plusnet <n...@home.com> wrote:

> On 23-May-23 21:20, Jerry Friedman wrote:

> > On Tuesday, May 23, 2023 at 2:02:25?PM UTC-6, Sam Plusnet wrote:
> >> On 22-May-23 23:16, Paul Wolff wrote:
> >>> On Mon, 22 May 2023, at 09:24:39, Jerry Friedman posted:
> >>>> "Vertex" also means the top of the head, by the way. I'm not sure at
> >>>> all that the meaning relating to angles is the oldest in Latin.
> >>>>
> >>> Nor I, but vertex to an educated Roman also meant whirlpool or eddy or
> >>> something else of that kind. And then there's fastigium, which seems to
> >>> have a kind of vertex-like meaning too.
> >
> >> Thank you.
> >> I shall in future refer to the top of my head as "Charybdis".
> >
> > That's very Scylly of you.
>
> What a monstrous claim!
>
> (I lack the hair required to make that 'whirl' atop my head.)

I have the maelstroom inside,

Jan

[Sam Plusnet]

I'll try the ungendered-stroom, if it's available.

--
Sam Plusnet

[Sam Plusnet]

You cheeky monkey.
--
Sam Plusnet

[J. J. Lodder]

It usually is, if you don't stroke the cat,

Jan

[Dingbat]

On Wednesday, May 24, 2023 at 5:30:10 PM UTC+5:30, Adam Funk wrote:
> On 2023-05-22, Paul Wolff wrote:
>
> > On Mon, 22 May 2023, at 09:24:39, Jerry Friedman posted:
> >>On Monday, May 22, 2023 at 10:21:370 >> While looking at my 16 year old niece's maths exam papers (as you do), I was
> >>> struck that the word "vertex" was used to describe the extremum of a
> >>>parabola.
> >>> I was suspicious of this usage because it seemed totally unrelated to
> >>> all other uses of "vertex" in mathematics. It isn't a point in a
> >>>graph, and it isn't
> >>> the intersection of two straight lines.
> >>> However, when I googled, I found that there is apparently a separate
> >>>definition
> >>> of "vertex" that means "extremum" and applies to parabolas only.
> >>> I find it very weird that someone apparently decided to wildly change
> >>>the usual
> >>> meaning of the word "vertex" and apply this new meaning to parabolas only,
> >>> when a perfectly good word, "extremum", already exists for the concept.
> >>>
> >>> Who could Adam and Eve it?
> >>
> >>Well, that meaning of the term isn't quite as old as Adam and Eve. (And yes,
> >>I got the rhyming slang.)
> >>
> >>"Vertex" also means the top of the head, by the way. I'm not sure at
> >>all that the meaning relating to angles is the oldest in Latin.
> >>
> > Nor I, but vertex to an educated Roman also meant whirlpool or eddy or
> > something else of that kind.
> >

<<Vortex and Vertex are merely alternate Latin spellings. Both come from "vertere
" meaning "to turn", with "vortex" being merely the archaic spelling of the term
and little-attested in classic texts.>>
https://www.reddit.com/r/etymology/comments/jbo6dq/vortex_and_vertex/
>
I ask:
If the source is vertere, how could vortex become an alternate Latin spelling?
Vowel harmony?
> >
FWIW: Sanskrit VARTULA circle seems the source of Tamil/ Malayalam
VATTAM, also meaning circle. Sanskrit neutralises a PIE E/O opposition
in many contexts making them both A, leaving little room for such alternative
spellings as VE... and VO...

> >
> > And then there's fastigium, which seems to
> > have a kind of vertex-like meaning too.
>

Fastigium Fever
<https://www.google.com/search?q=fastigium+fever>

>
> "A Descent into the Vertex" doesn't have the same ring to it.
>

It doesn't sound like Charybdis. In English, at any rate.

[Dingbat]

Cute, but Glaucus called her Skullah.

[Adam Funk]

On 2023-05-22, Jerry Friedman wrote:

> On Monday, May 22, 2023 at 10:24:42 AM UTC-6, Jerry Friedman wrote:

>> On Monday, May 22, 2023 at 10:21:37 AM UTC-6, Paul Epstein wrote:
>> > While looking at my 16 year old niece's maths exam papers (as you do), I was
>> > struck that the word "vertex" was used to describe the extremum of a parabola.
>> > I was suspicious of this usage because it seemed totally unrelated to
>> > all other uses of "vertex" in mathematics. It isn't a point in a graph, and it isn't
>> > the intersection of two straight lines.
>> > However, when I googled, I found that there is apparently a separate definition
>> > of "vertex" that means "extremum" and applies to parabolas only.
>> > I find it very weird that someone apparently decided to wildly change the usual
>> > meaning of the word "vertex" and apply this new meaning to parabolas only,
>> > when a perfectly good word, "extremum", already exists for the concept.
>> >
>> > Who could Adam and Eve it?
>> Well, that meaning of the term isn't quite as old as Adam and Eve. (And yes,
>> I got the rhyming slang.)
>>

>> "Vertex" also means the top of the head, by the way. I'm not sure at
>> all that the meaning relating to angles is the oldest in Latin.
>

> OK, now I'm sure. The AHD says the etymology is
>
> "Latin, whirlpool, crown of the head (where the hair forms a whorl), vertex,
> from /vertere/, to turn; see *wer-2* in the Appendix of Indo-European roots."
>
> "Vortex" is a variant of "vertex".

Although my hair is less curly than it used to be, I'm not sure if I
have a whorl.


--
it's the nexus of the crisis
and the origin of storms

[Jerry Friedman]

On Tuesday, May 23, 2023 at 6:46:00 PM UTC-6, Sam Plusnet wrote:
> On 23-May-23 20:43, Jerry Friedman wrote:
> > On Tuesday, May 23, 2023 at 7:01:52 AM UTC-6, Dingbat wrote:
> >> On Monday, May 22, 2023 at 9:51:37 PM UTC+5:30, Paul Epstein wrote:
> > ...
> >
> >>> Who could Adam and Eve it?
> >>> :
> >> Cockney rhyming slang, this says:
> >> <https://www.phrases.org.uk/idioms/would-you-adam-and-eve-it.html>
> >> 1) Where's the rhyme?
> >
> > With the definition it gave.
> >
> >> 2) Is it everyone's idiom now?
> >
> > I've never heard it.
> >
> > I was interested to see that they listed it with "would you". Does that mean
> > one can't replace other uses of "believe" with "Adam and Eve"? "Well, I
> > Adam and Eve it"? "I don't think they Adam and Eved me"?

> At one time?
> Maybe one could - but it has pretty much fossilised into just that one
> exclamation:
>
> "Well! Would you Adam and Eve it!"

Thanks, just curious about English usage.

> An equivalent I haven't heard for a few years is:
>
> "Well! I'll go to the foot of our stairs!"
>
> Sheer nonsense, but it served its purpose.

I'm looking for an opportunity to use that one. Should baffle everyone
in New Mexico.

Maybe it's a euphemism for "I'll go (hopping) to hell", which Green dates
to 1957. Shockingly enough, Green doesn't have anything about the foot
of our stairs.

--
Jerry Friedman

[Jerry Friedman]

In an Indo-European language?

> FWIW: Sanskrit VARTULA circle seems the source of Tamil/ Malayalam
> VATTAM, also meaning circle. Sanskrit neutralises a PIE E/O opposition
> in many contexts making them both A, leaving little room for such alternative
> spellings as VE... and VO...

...

The reddit poster may have been oversimplifying a bit in saying "vortex"
came from "vertere". The OED says "vortex" is

"< Latin /vortex/ (variant of /vertex/ vertex n.) an eddy of water, wind, or
flame, a whirlpool, whirlwind, < /vortĕre, vertĕre/ to turn."

As for whether "vortere" came from PIE *wer- via one of those e-o
variations, you'd have to ask someone who knows more about this
stuff than I do.

--
Jerry Friedman

[Dingbat]

On Thursday, May 25, 2023 at 10:36:04 PM UTC+5:30, Jerry Friedman wrote:
> On Thursday, May 25, 2023 at 2:41:04 AM UTC-6, Dingbat wrote:

> > <<Vortex and Vertex are merely alternate Latin spellings. Both come from "vertere
> > " meaning "to turn", with "vortex" being merely the archaic spelling of the term
> > and little-attested in classic texts.>>
> > https://www.reddit.com/r/etymology/comments/jbo6dq/vortex_and_vertex/
> > >
> > I ask:
> > If the source is vertere, how could vortex become an alternate Latin spelling?
> > Vowel harmony?
> In an Indo-European language?

As IE languages gained speakers, they got influenced by new speakers'
former languages.

[Kerr-Mudd, John]

Werl, my mind's in a whirl.

>
> --
> it's the nexus of the crisis
> and the origin of storms

[Peter T. Daniels]

"Language shift" is a very rare phenomenon.

You may want to look into "substrate" and "language contact."

[bruce bowser]

As much as old speakers' foreign languages?

[Sam Plusnet]

Are you whirldly wise?

--
Sam Plusnet

[Peter Moylan]

On 26/05/23 03:05, Jerry Friedman wrote:
> On Thursday, May 25, 2023 at 2:41:04 AM UTC-6, Dingbat wrote:

>> I ask: If the source is vertere, how could vortex become an
>> alternate Latin spelling? Vowel harmony?
>
> In an Indo-European language?

Nothing to do with vowel harmony, but I thought that vowel changes were
common in IE languages. You can hear the vowels changing, in a single
language, as you move from one dialect area to another.

--
Peter Moylan Newcastle, NSW http://www.pmoylan.org

[Peter T. Daniels]

On Friday, May 26, 2023 at 10:32:55 PM UTC-4, Peter Moylan wrote:
> On 26/05/23 03:05, Jerry Friedman wrote:
> > On Thursday, May 25, 2023 at 2:41:04 AM UTC-6, Dingbat wrote:

> >> I ask: If the source is vertere, how could vortex become an
> >> alternate Latin spelling? Vowel harmony?
> > In an Indo-European language?
>
> Nothing to do with vowel harmony, but I thought that vowel changes were
> common in IE languages. You can hear the vowels changing, in a single
> language, as you move from one dialect area to another.

See under "Ablaut." Not a dialect thing, but what remnants of are seen
in sing sang sung song (note both inflection and derivation).

[Peter Moylan]

But can't this be broken down into two categories? The sing/sang/sung
thing is just a matter of inflection, similar to Germanic umlaut: the
use of different vowels to indicate different noun cases, different verb
tenses, etc. The fact that vowels can be different in different dialects
of the same language is not inflection, but a variation caused by the
fact that populations can drift in their pronunciation.

[Peter T. Daniels]

On Saturday, May 27, 2023 at 10:40:53 AM UTC-4, Peter Moylan wrote:
> On 27/05/23 23:56, Peter T. Daniels wrote:
> > On Friday, May 26, 2023 at 10:32:55 PM UTC-4, Peter Moylan wrote:
> >> On 26/05/23 03:05, Jerry Friedman wrote:
> >>> On Thursday, May 25, 2023 at 2:41:04 AM UTC-6, Dingbat wrote:

> >>>> I ask: If the source is vertere, how could vortex become an
> >>>> alternate Latin spelling? Vowel harmony?
> >>> In an Indo-European language?
> >> Nothing to do with vowel harmony, but I thought that vowel changes
> >> were common in IE languages. You can hear the vowels changing, in a
> >> single language, as you move from one dialect area to another.
> > See under "Ablaut." Not a dialect thing, but what remnants of are
> > seen in sing sang sung song (note both inflection and derivation).
>
> But can't this be broken down into two categories? The sing/sang/sung
> thing is just a matter of inflection, similar to Germanic umlaut: the
> use of different vowels to indicate different noun cases, different verb
> tenses, etc.

Yes, that's "the use of different vowels to indicate different noun cases, different
verb tenses, etc." It was clearest to the founders of IE philology in Sanskrit, but
the Germanic, Greek, and even Latin patterns all show the same things.

> The fact that vowels can be different in different dialects
> of the same language is not inflection, but a variation caused by the
> fact that populations can drift in their pronunciation.

Which has nothing to do with the structure of (P)IE. Variation-and-change
is ubiquitous and inevitable.