I happened upon an image on the Internet

weird math 1
(source: news.com.au)

and I wondered whether the math on the chalkboard means anything. Using Google's image search, I found three other related images.

weird math 2

weird math 3

weird math 4
(source: nees.org)

Piecing together the math from the various angles shows some mismatched grouping symbols.

My question: Ignoring the possible typos, does the "math" mean anything? Or is this an example of stock photography trying to appear mathy?

  • $\begingroup$ It's almost an integral, but written weirdly. $\endgroup$ – user223391 May 22 '15 at 16:26
  • 3
    $\begingroup$ Looks like someone copied something they didn't understand. If instead of the curly bracket $\{$ they had written an integral sign $\int$, then they appear to be something like the formulae for Fourier series/transform. $\endgroup$ – Simon S May 22 '15 at 16:26
  • 11
    $\begingroup$ You'd have to ask the guy pointing very proudly at $$1/PI\big\{_{-\infty}^\infty\ f(t) \sin ty\ dt,$$ I think he just discovered its meaning. $\endgroup$ – pjs36 May 22 '15 at 16:28
  • 1
    $\begingroup$ So the best suggestion is to replace $\{$ with $\int$ and $PI$ with $\pi$. $\endgroup$ – Hagen von Eitzen May 22 '15 at 16:50
  • 2
    $\begingroup$ I remember I have seen an OCR software which have mistaken the integral sign $\int$ as the parenthesis when extracting math from old book. So the { part doesn't look too strange to me. In fact, the $acy |$ on the second line also looks like an OCR mistake to me (the original should be $a(y)$). $\endgroup$ – achille hui May 22 '15 at 17:05

Googling fourier "a(y)" "b(y)" yields this first hit:

Fourier Integral of the function f(x)

  • 2
    $\begingroup$ +1 It looks like this is the original text for what's on the board. What the board is showing is the output of the text under OCR. $\endgroup$ – achille hui May 22 '15 at 17:24
  • 1
    $\begingroup$ while I am happy to have gotten 180 points for essentially nothing, this is the right answer and should be accepted! $\endgroup$ – hunter May 22 '15 at 20:04
  • $\begingroup$ Very nice find via Google! $\endgroup$ – Tim Thayer May 23 '15 at 18:12
  • $\begingroup$ Thanks @hunter ! Your endorsement has boosted my rep past the 2k threshold $\endgroup$ – grand_chat May 23 '15 at 20:46

It's safe to say that the math doesn't mean anything. No branch of mathematics or science or anything else uses the symbol $\{$ for an integral sign, and there are mismatched parentheses.


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