# Log24

## Saturday, September 6, 2014

### Infinite Jest

Filed under: General,Geometry — Tags: , — m759 @ 9:18 AM

“1 + 2 + 3 + … = –1/12.”

Robin Williams and the Stages of Math

i)   shock & denial
ii)  anger
iii) bargaining
iv) depression
v)  acceptance

And then…

vi)  checking
vii) Joan Rivers:

## Friday, September 5, 2014

### Flashback

Filed under: General — Tags: — m759 @ 9:16 AM

The date at the end of yesterday’s noon post was May 25, 2010.
This, together with Keith Devlin’s Twitter page today, suggests
a review of that date.

Res ipsa loquitur.

## Thursday, September 4, 2014

### Halloween Manifestos, 2013:

Filed under: General,Geometry — Tags: — m759 @ 12:00 PM

— and part of an interesting Sept. 2, 2014, manifesto by
Common Core supporter Keith Devlin:

“Graduate students of mathematics are introduced to further
assumptions (about handling the infinite, and various other issues),
equally reasonable and useful, and in accord both with our everyday
intuitions (insofar as they are relevant) and with the rest of
mainstream mathematics. And on the basis of those assumptions,
you can prove that

1 + 2 + 3 + … = –1/12.

That’s right, the sum of all the natural numbers equals –1/12.

This result is so much in-your-face, that people whose mathematics
education stopped at the undergraduate level (if they got that far)
typically say it is wrong. It’s not. Just as with the 0.999… example,
where we had to construct a proper meaning for an infinite decimal
expansion before we could determine what its value is, so to we
have to define what that infinite sum means. ….”

For a correction to Devlin’s remarks, see a physics professor’s weblog post —

“From a strictly mathematical point of view,
the equation 1+2+3+4+ … = -1/12 is incorrect,
and involves confusing the Dirichlet series with
the zeta function.”  — Greg Gbur, May 25, 2010

## Sunday, July 13, 2014

### Useful Princeton

Filed under: General — Tags: , — m759 @ 10:30 AM

See…

"Numbers themselves are fictions, abstractions humans invented
to gain more control over the world." — Keith Devlin

Related material:

## Wednesday, July 2, 2014

### An Apple for Devlin

Filed under: General — Tags: — m759 @ 2:56 PM

A columnist for the Mathematical Association of America,
Keith Devlin, yesterday posted an essay on Common Core
math education. A response:

Screenshot from a June 14, 2014, New York Times  video.