https://thoughtstreams.io/Dave/til/TILDave2018-01-23T10:28:59Zhttps://thoughtstreams.io/Dave/til/#card-12092> One of the most surprising things a...2018-01-23T10:28:59Z2018-01-23T10:28:59Z
> One of the most surprising things about electronic mail is the ease with which misinterpretations arise
was a 1985 sentiment from RAND report R3283, "Toward an Ethics and Etiquette for Electronic Mail". Now I'm imagining ca. 2005 Odeo looking at email and exclaiming "hold my beer!"
https://thoughtstreams.io/Dave/til/#card-12003 Giuseppe Peano was evidently a bit j...2017-10-04T10:11:12Z2017-10-04T10:11:12Z
Giuseppe Peano was evidently a bit jealous of Leibniz' XVII ability to publish things like:
![Image L.png](/media/640/Image%20L.png)
(to express commutativity and idempotency), for
even in the late XIX he expresses himself anachronistically:
![Image 3.png](/media/639/Image%203.png)
(Peano's versions of his symbols make better ping-pong paddles than our modern variants!)
Evidently Peano went even further than Schröder's [Pasigraphy](https://thoughtstreams.io/Dave/til/11996/)
, proposing not only the formal notation for which we remember him, but even a [creolized Latin](https://en.wikipedia.org/wiki/Latino_sine_flexione) to serve as a scientific conlang for informal argument ... but he wasn't foolish enough to attempt to revive [greek](https://thoughtstreams.io/Dave/αρχαιοελληνικαι-μουσική-και-ταινίες/10762/
)!
* Peano, [Arithmetices Principia: nova methodo exposita](https://archive.org/details/arithmeticespri00peangoog) (1889) p. viii
* Leibniz [Addenda ad Specimen Calculi Universalis](https://books.google.ch/books?id=C5LRAAAAMAAJ&hl=fr&pg=PA98) (ca. 1680) p. 1
https://thoughtstreams.io/Dave/til/#card-11996TIL Ernst Schröder would've have to w...2017-10-02T16:22:22Z2017-10-02T16:22:22Z
TIL Ernst Schröder would've have to wait nearly 80 years* —with the intervening invention of the computer — for his late XIX logical notation:
![Image 2.png](/media/636/Image%202.png)
(here intended as part of a universal formal "pasigraphy", as communicated to an international mathematical conference in Zürich) to find yet another application: as a simpler, if unfortunately far too earlier, alternative to [predicate transformer semantics](http://www.cs.utexas.edu/users/EWD/ewd04xx/EWD472.PDF).
* „Über Pasigraphie, ihren gegenwärtigen Stand und die
pasigraphische Bewegung in Italien‟, 1897
https://thoughtstreams.io/Dave/til/#card-11970Older Siemens ES64U locomotives had s...2017-09-18T13:46:12Z2017-09-18T13:46:12Z
Older Siemens ES64U locomotives had sidelobes in the audio range during initial acceleration ... but someone decided this bug could be a feature, and so they played a distinct do-re-mi.
https://thoughtstreams.io/Dave/til/#card-11965Youtube: not only good for pseudorand...2017-09-13T15:43:50Z2017-09-13T15:43:50Z
Youtube: not only good for pseudorandomly encountering pop music from other cultures, but also serves as an unusually diverse mirroring medium for linux distros:
https://www.youtube.com/watch?v=edw7HXke8ho
https://thoughtstreams.io/Dave/til/#card-11416(not from today, but...) it's not jus...2017-03-17T06:38:39Z2017-03-17T06:38:39Z
(not from today, but...) it's not just [Mexico and the US](https://thoughtstreams.io/rrees/til/11415/); "coca-cola" is more a brand than a specific [flavor](http://www.coca-cola.co.uk/faq/does-coca-cola-produce-the-same-drinks-in-every-country).
[Edit: ... and for people who live in sufficiently cosmopolitan parts of the US, sugar-sweetened coca-cola can be found]
https://thoughtstreams.io/Dave/til/#card-11406TIL about the [Turpan](https://en.wik...2017-03-15T09:08:16Z2017-03-15T09:08:16Z
TIL about the [Turpan](https://en.wikipedia.org/wiki/Turpan_water_system) hydraulic engineering. I found it especially interesting, because just behind my house is one of our local (above-ground) canals, conducting glacial melt from the alpine valleys above to the [grapes and apricots](http://www.bbc.com/travel/story/20170307-an-ancient-oasis-in-chinas-remote-desert) growing below.
https://thoughtstreams.io/Dave/til/#card-11400Donald John Trump (R - US) [45,9%](ht...2017-03-10T14:19:50Z2017-03-10T14:19:50Z
Donald John Trump (R - US) [45,9%](https://en.wikipedia.org/wiki/United_States_presidential_election,_2016)
Vladimir Vladimirovich Putin (EdRo - RU) [63,6%](https://en.wikipedia.org/wiki/Russian_presidential_election,_2012)
Fidel Alejandro Castro Ruz (PCC - CU) [94,73%](https://fr.wikipedia.org/wiki/Élections_législatives_cubaines_de_2013)
Jefferson Beauregard Sessions (R - US) [97,25%](https://en.wikipedia.org/wiki/United_States_Senate_election_in_Alabama,_2014)
https://thoughtstreams.io/Dave/til/#card-11379**POST TENEBRAS LVX**
TIL the Repu...2017-02-22T08:35:55Z2017-02-22T08:35:55Z
**POST TENEBRAS LVX**
TIL the Republic and Canton of Geneva has a nifty motto, thanks to following the architectural [references](https://en.wikipedia.org/wiki/Reformation_Wall) in Geneva's entry in the grand [tradition](https://www.youtube.com/watch?v=ELD2AwFN9Nc) of [#2 videos](http://www.everysecondcounts.eu/europe.html):
"Geneva second | Genève interpelle Donald Trump"
https://www.youtube.com/watch?v=tV_KBUM3yK8
> c'est toujours le plus intelligent qui cède
https://thoughtstreams.io/Dave/til/#card-11343In a world where Poe's Law appears to...2017-02-13T08:47:57Z2017-02-13T08:47:57Z
In a world where Poe's Law appears to reign supreme, one can always peruse [abstract comics](http://abstractcomics.blogspot.ch/). They have the graphical syntax of comics, but lack semantics. Might they be the grandchild of Dada?
https://thoughtstreams.io/Dave/til/#card-11244The soviet-era Elbrus computer line w...2016-12-31T15:14:04Z2016-12-31T15:14:04Z
The soviet-era Elbrus computer line was based on the same B5000 that many software people consider "an improvement upon nearly all its successors" (unfortunately for Burroughs' reception in the marketplace, their peripherals may not have been so reliable: worse is better, except when it isn't).
TIL the Elbrus tradename is still [in commercial use](http://www.mcst.ru/), although these days it looks as if it's being slapped on systems running Linux on SPARC derivatives instead.
However, if the RF equivalent of "orange book" systems buyers still can source something with the safety properties of the old MCP lineage, it might help explain the recently infamous « русский хакер ». After all, if you live in a wooden house, with roughly capability-based security, while your neighbor's glass house is chock full of legacy x86 and C/C++, it must take an awful lot of willpower to avoid throwing stones...
https://thoughtstreams.io/Dave/til/#card-11196TIL about a Cousot et Cousot paper on...2016-12-18T22:15:52Z2016-12-18T22:15:52Z
TIL about a Cousot et Cousot paper on [Galois Connections](http://www.di.ens.fr/~rcousot/publications.www/CousotCousot-POPL14-ACM-p2-3-2014.pdf) ... well, actually it's (as one might guess from the topic?) a pair of papers: one of which is the expanded concrete representation, the other of which is a compressed (albeit still containing most of the important bits) abstract representation.
https://thoughtstreams.io/Dave/til/#card-11083TIL about the [Inukshuk](https://en.w...2016-11-06T17:01:38Z2016-11-06T17:01:38Z
TIL about the [Inukshuk](https://en.wikipedia.org/wiki/Inuksuk), an arctic cairn style.
![Inukshuk](http://a133.idata.over-blog.com/3/39/66/92/nounours/95-inukshuk.jpg)
https://thoughtstreams.io/Dave/til/#card-10760TIL the intersection, [doo wop songs ...2016-08-08T14:08:28Z2016-08-08T14:08:28Z
TIL the intersection, [doo wop songs & Studentenlieder](https://www.youtube.com/watch?v=S_OblYW1uvc), is non-empty.
MVNDVS MIRABILIS
https://thoughtstreams.io/Dave/til/#card-10752TIL how to [trick a neural network in...2016-08-04T13:28:41Z2016-08-04T13:28:41Z
TIL how to [trick a neural network into thinking a panda is a vulture](https://codewords.recurse.com/issues/five/why-do-neural-networks-think-a-panda-is-a-vulture)
* (I wonder if the same principle: "it doesn't matter if it's not a vulture as long as the weights add up to vulturish" applies to "it [doesn't matter if it's not journalism](https://thoughtstreams.io/Kake/bite-sized-reading/10743/) as long as the ad buys add up to journalistic"?)
https://thoughtstreams.io/Dave/til/#card-10725TIL [@michaelbolton](https://mobile.t...2016-07-26T00:35:25Z2016-07-26T00:35:25Z
TIL [@michaelbolton](https://mobile.twitter.com/michaelbolton) *is* a programmer. I failed to learn, however, if he knows what "PC LOAD LETTER" means.
https://thoughtstreams.io/Dave/til/#card-10617By way of [Bunnie](http://bunniestudi...2016-06-19T09:54:28Z2016-06-19T09:54:28Z
By way of [Bunnie](http://bunniestudios.com/bunnie/phdthesis.pdf), TIL Gordon Moore may not have predicted current fashions (and was a little pessimistic about the size of smartphones), but he definitely knew —a half century ago— how pursetop computers would be marketed:
![Image 1.png](/media/449/Image%201.png)
https://thoughtstreams.io/Dave/til/#card-10551TIL that not only is a « zapaska » a ...2016-06-03T10:03:48Z2016-06-03T10:03:48Z
TIL that not only is a « zapaska » a "stepney" in english
![zapaska](http://cs543104.vk.me/v543104286/143a9/WAy1rvj1y9w.jpg)
(thank you, Dyadya Google)
but also that a "stepney" is neither cisatlantic nor translatlantic, but [transpacific](http://www.bbc.co.uk/ahistoryoftheworld/objects/qPgTiS8fQ6SeIqZLvZVfXQ). (thank you Auntie Beeb).
https://thoughtstreams.io/Dave/til/#card-10391*On Hills and Dales*, although publis...2016-05-03T07:16:10Z2016-05-03T07:16:10Z
*On Hills and Dales*, although published almost a century and a half ago in *Philosophical Magazine* is surprisingly (at least in my search engine bubble?) difficult to find in full text. Best I could do was [p.233, paper XLIII](http://strangebeautiful.com/other-texts/maxwell-scientificpapers-vol-ii-dover.pdf) in a collection of Maxwell's works.
![Image 4.png](/media/431/Image%204.png)
Is there an anglophone equivalent of [Gallica](http://gallica.bnf.fr/)?
Edit: [Cayley](https://thoughtstreams.io/Dave/til/8049/)'s 1859 [On Contour and Slope Lines](http://www.maths.ed.ac.uk/~aar/papers/cayleyconslo.pdf) was, happily, more readily available.
https://thoughtstreams.io/Dave/til/#card-10339The first log tables were laboriously...2016-04-27T09:20:42Z2016-04-27T09:20:42Z
The first log tables were laboriously hand calculated once, and then apparently cut'n'pasted from one application to another for the [following three centuries](http://www.feynmanlectures.caltech.edu/I_22.html):
> all logarithm tables for three hundred years were borrowed from Mr. Briggs’ tables by reducing the number of decimal places
Today, computation is *too cheap to meter* and one can program the necessary calculation, even without `import math`, in a matter of minutes. Obtaining the patterns required to make the insights necessary to get to \( \mathbb{C} \) when given \( \mathbb{N} \) ... might take a bit longer.
# after http://www.feynmanlectures.caltech.edu/I_22.html#footnote_source_1
_=min
sqrt = lambda n: _( cvg(nstep(n1))(n1)
for n1 in [float(n)]
for cvg in [lambda f: lambda x:
_( x if y==x else cvg(f)(y)
for y in [f(x)] )]
for nstep in [lambda n: lambda g: (n/g+g)/2] )
if __name__ == "__main__":
def D(x):print(x);return x
# regenerate table 22-1 from feynman LoP
n = 10
for i in range(16): n = sqrt(D(n))
# check precision after inverting
for i in range(16): n = n*n
print(n,n - 10.)
https://thoughtstreams.io/Dave/til/#card-10334The sequence:
0 → algebra scenes →...2016-04-26T08:56:55Z2016-04-26T08:56:55Z
The sequence:
0 → algebra scenes → hollywood movies → profit → 0
fails to be exact at small values of "profitable":
It's My Turn (1980) [Snake Lemma](https://en.wikipedia.org/wiki/Snake_lemma)
https://www.youtube.com/watch?v=etbcKWEKnvg
https://thoughtstreams.io/Dave/til/#card-10137The "Alabama Song" was originally wri...2016-03-11T15:37:02Z2016-03-11T15:37:02Z
The "Alabama Song" was originally written (in english) for a Brecht work (which was then performed in german) in the 20's, before being covered by the Doors (in english) in the 60's.
https://thoughtstreams.io/Dave/til/#card-8049Cayley not only introduced the term "...2015-04-08T10:07:53Z2015-04-08T10:07:53Z
Cayley not only introduced the term "tree" (in the CS sense) to the english language in [1857](http://books.google.ch/books?id=MlEEAAAAYAAJ&pg=PA172&redir_esc=y#v=onepage&q&f=false), he did so *as a computer scientist*:
- his motivation was abstract parses of concrete syntax
- his investigation distinguishes between commutative and associative operations, and
- his trees have their roots at the top, and their branches opening downwards!
![Image 13.png](/media/283/Image%2013.png)
https://thoughtstreams.io/Dave/til/#card-7668According to Hamming, the naming inst...2015-02-28T15:44:46Z2015-02-28T15:44:46Z
According to Hamming, the naming instance of Gibbs' phenomena was due to investigating an unexpected behavior of Michelson's [mechanical fourier analyzer](https://thoughtstreams.io/Dave/til/6862/) ... not just chalking it up to experimental error.
("The Art of Doing Science and Engineering", pp109-110)
https://thoughtstreams.io/Dave/til/#card-7403The [J language](https://twitter.com/...2015-01-30T12:36:42Z2015-01-30T12:36:42Z
The [J language](https://twitter.com/search?q=%23JLang) hashtag has a high (proper!) ratio of models to lines of source code.
(upon investigation, #JLang might have a maximal intersection of "fashion models" with "source code", not just for programming hashtags, but also —despite Amazon's best efforts at searchspam— for the web in general)
https://thoughtstreams.io/Dave/til/#card-7214From when "spaghetti code" was meant ...2015-01-08T09:33:12Z2015-01-08T09:33:12Z
From when "spaghetti code" was meant literally: how [adders](http://www.columbia.edu/cu/computinghistory/tabulator.html) could multiply (w/out logs):
![4x4 multiplication](/media/237/Image%2012.png)
Boyell, "Programmed Multiplication on the IBM 407" (1957)
https://thoughtstreams.io/Dave/til/#card-7174Once upon a time, an investor related...2014-12-30T15:11:15Z2014-12-30T15:11:15Z
Once upon a time, an investor related an old story about working on some government contract involving vector displays costing thousands, if you could source them at all ... and then being shocked to discover Vectrexen being sold in Sears for under USD 200.
TIL that in the early 80's, game companies didn't just buy displays, they did some [serious](http://www.jmargolin.com/vgens/vgens.htm) [engineering](http://www.jmargolin.com/xy/xymon.htm) to meet their price points via hw/sw codesign.
https://thoughtstreams.io/Dave/til/#card-7081the idea of [Artificial Neural Networ...2014-12-10T09:16:08Z2014-12-10T09:16:08Z
the idea of [Artificial Neural Networks](http://www.minicomplexity.org/pubs/1943-mcculloch-pitts-bmb.pdf) is now over 70 years old.
https://thoughtstreams.io/Dave/til/#card-7033Iron oxides are not only [abundant](h...2014-12-05T09:47:54Z2014-12-05T09:47:54Z
Iron oxides are not only [abundant](https://thoughtstreams.io/rrees/til/#card-7000), they globally occur on a geologic scale in large, layered "Banded Iron Formations"; what I was taught about these seems to still be the [conventional wisdom](http://en.wikipedia.org/wiki/Banded_iron_formation#Origins), namely that they're a highly visible side effect left over from when the biosphere discovered photosynthesis.
https://thoughtstreams.io/Dave/til/#card-6947the null program, at least by [certai...2014-11-30T18:55:06Z2014-11-30T18:55:06Z
the null program, at least by [certain measures](http://blog.racket-lang.org/2010/02/dags-vs-trees.html), has manifold ramifications — more than the typical filesystem.
https://thoughtstreams.io/Dave/til/#card-6862In the XIX, FMACs were done with spri...2014-11-19T10:52:55Z2014-11-19T10:52:55Z
In the XIX, FMACs were done with springs (and clocked via handcrank): https://www.youtube.com/watch?v=6dW6VYXp9HM
https://thoughtstreams.io/Dave/til/#card-6767The chance that an arbitrary permutat...2014-11-14T22:17:32Z2014-11-14T22:17:32Z
The chance that an arbitrary permutation doesn't have *any* fixed points tends to 1/e.
(is this any relation to the 1/e that shows up in [optimal stopping](http://en.wikipedia.org/wiki/Secretary_problem) heuristics?)
https://thoughtstreams.io/Dave/til/#card-6562I'd always thought Landin's "Program ...2014-10-29T17:47:25Z2014-10-29T17:47:25Z
I'd always thought Landin's "Program Machine Symmetric Automata Theory" (Machine Intelligence 5) rather imaginative:
>"Suppose a directed graph with coloured edges is drawn on a plane, and another one drawn on the surface of a sphere. Imagine the sphere rolling ... on the plane, but constrained in such a way that the point of contact follows ... both graphs ... synchronizing the vertices and matching the colours.
TIL that [mid-XX fire control](http://hackaday.com/2014/10/28/retrotechtacular-fire-control-computers-in-navy-ships/#more-135692) actually involved computations via rolling (albeit continuously) spheres on planes.
(to paraphrase Körner: that these have been obsoleted by digital systems probably says more about human technological than moral progress over the last several decades)
https://thoughtstreams.io/Dave/til/#card-6320bis quinque figuris: (_Carmen de Algo...2014-10-14T23:12:18Z2014-10-14T23:12:18Z
bis quinque figuris: (_Carmen de Algorismo_)
![Image 7.png](/media/223/Image%207.png)
https://thoughtstreams.io/Dave/til/#card-6263Aristotle's *Organon* roughly transla...2014-10-07T10:37:39Z2014-10-07T10:37:39Z
Aristotle's *Organon* roughly translates to "instrument, tool".
Was "Notation as a [Tool](http://www.jsoftware.com/papers/tot.htm) of Thought" a conscious tip of the hat to the Stagirite?
(much less likely, but possible: was this title simply a metasyntactic variable Aristotle's students used to refer to his lecture notes? — cf fr. *truc*)
https://thoughtstreams.io/Dave/til/#card-6252Resolving two clauses with more than ...2014-10-03T10:27:56Z2014-10-03T10:27:56Z
Resolving two clauses with more than one pair of complementary literals always yields tautology.
(formally, the absorption works almost identically to the well-known physical notion that ∂∂=0 "boundaries are unbounded". I have not yet learned whether there is anything more to this correspondence than the simple observation that a logical formula represents –cf Karnaugh– a "Truth polygon"...)
https://thoughtstreams.io/Dave/til/#card-6075"These twice five figures" with which...2014-09-25T21:34:55Z2014-09-25T21:34:55Z
"These twice five figures" with which we count are clearly related to our five fingers[0].
But why five? TIL that it's a few hundred-million-year [backward compatibility](http://genepath.med.harvard.edu/~tabin/Pdfs/Tabin4.pdf) issue:
>Because there are only five distinct Hox-encoded domains across the limb bud there
is a developmental constraint prohibiting the evolution of more than five different types of digits.
[0] at least when counting moving objects, such as cattle; bakers, whose objects tend to stay where one left them, use nicer rectangles, and hence prefer dozens to tens.