Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Where and When Did the Symbols "+" and "–" Originate?

blogs.stsci.edu

Post reply on HN
Print view View original

71–80 of 90 posts

Re: Where and When Did the Symbols "+" and "–" Originate?

#71

Post by xerula »

znowi wrote: post #56
xerula wrote: post #12

Earlier quoted context omitted.

On the temporal / spatial scale of the universe we are virtually non-existent. On a scale that ranks everything in the universe according to physical / informational complexity & organization, we appear so far to be quite significant.

Our yardstick is far too short to make any universe scale ranking on this subject. However, what we lack in knowledge, we thoroughly compensate in sense of ego and self-importance as species :)

Our yardstick is pretty good. We have characterized a vast range of the objects we share out universe with in immense structural detail, from lifeforms here on earth to astronomical objects billions of light years away. The human brain sticks out.

I wrote my comment precisely because it has become a cliché to say what you're saying – how small, ignorant and insignificant we are in relation to the universe, how we compensate by being arrogant. Taking a different view, that human brains are really quite extraordinary compared to everything we can see out there, is not necessarily egotistic. The more I feel a sense of wonder at the preciousness and privilege of human life, the more I want to spend mine being helpful, nurturing, productive.

:)

Re: Where and When Did the Symbols "+" and "–" Originate?

#72

Post by Retric »

xerula wrote: post #71
znowi wrote: post #56

Earlier quoted context omitted.

Our yardstick is far too short to make any universe scale ranking on this subject. However, what we lack in knowledge, we thoroughly compensate in sense of ego and self-importance as species :)

Our yardstick is pretty good. We have characterized a vast range of the objects we share out universe with in immense structural detail, from lifeforms here on earth to astronomical objects billions of light years away. The human brain sticks out. I wrote my comment precisely because it has become a cliché to say what you're saying – how small, ignorant and insignificant we are in relation to the universe, how we com…

We know a lot about a tiny area, and a tiny amount about a large area. But, suggesting we know anything about life / AI outside our solar system is pure hubris.

Re: Where and When Did the Symbols "+" and "–" Originate?

#73

Post by Moto7451 »

kzrdude wrote: post #68
simonh wrote: post #54

Earlier quoted context omitted.

My best guess would be that we use * for multiplication because x being alphanumeric is a valid variable name. regarding keyboard presence, this is one of the things that irks me about Mac keyboards is the absence of the # character. I write little programs and scripts on my mac infrequently enough that I have to look up how to type it every blasted time. That, and how to take screenshots. The "Print Scrn" key on PCs…

Some apple keyboards have # printed, I'm surprised they don't all have it.

I'm going to assume he has the British keyboard which has a pound symbol rather than the hash (or... pound...) symbol.

http://parkernet.com/applepro/images/wireless-british.jpg

Re: Where and When Did the Symbols "+" and "–" Originate?

#74

Post by scott_s »

milliams wrote: post #44
scott_s wrote: post #41

Earlier quoted context omitted.

To be fair, I prefer dots over crosses for multiplication of scalars in when I write it myself. I tend to assume a cross means cross product instead of scalar multiplication. (But, oddly, I do not assume that a dot means dot product.)

But even in that case, people are using the full-stop '.' rather than the middle dot '·'

They are? I use a middle dot. (I'm talking about when I write on paper or a board.)

Re: Where and When Did the Symbols "+" and "–" Originate?

#75

Post by jewbacca »

Uncompetative wrote: post #62
simonh wrote: post #54

Earlier quoted context omitted.

My best guess would be that we use * for multiplication because x being alphanumeric is a valid variable name. regarding keyboard presence, this is one of the things that irks me about Mac keyboards is the absence of the # character. I write little programs and scripts on my mac infrequently enough that I have to look up how to type it every blasted time. That, and how to take screenshots. The "Print Scrn" key on PCs…

X = Y x Z B = T ^ F v T P = Q n R u S C = U cross V D = U dot V Area = Width by Height i.e. just capitalising names means that you can define macros that operate as infix operators: L . R -> L dot R L dot R -> Dot[L, R]

What language are you referring to? I'm not quite sure I understand your examples.

--------

Related:

In Haskell, any 2-argument function can be used (or defined) infix by surrounding it with backticks, eg:

    add 2 3
is equivalent to:

    2 `add` 3
----

And you can use this to cleanly write curried functions (often predicates) with their arguments flipped, eg:

    vowelCount = length . filter (`elem` "aeiou")
----

Note that functions named with punctuation characters are infix by default, and one can be used/defined prefix by surrounding it with brackets, eg:

    () = fmap
    toUpper  "aeiou"    # => "AEIOU"
----

It's also convenient for resolving a subset of one of the harder problems in computer science: naming things. For a 2-argument function, use it infix and read it as a phrase in english. Which is clearer:

    ".jpg" `isSuffix` url
or:

    ".jpg" `isSuffixOf` url
You can also define functions' precedence and associativity (left/right) when used as an infix operator.

Re: Where and When Did the Symbols "+" and "–" Originate?

#76

Post by Peaker »

tel wrote: post #46
sp332 wrote: post #42

Earlier quoted context omitted.

We already tried going full-APL but it only proved that it wasn't a good idea. I mean this is impressive https://www.youtube.com/watch?v=a9xAKttWgP4 but I still think the notation is too obscure.

Full APL isn't just unicode, though, it's also a total commitment to single-character operators as the primary language construct. Take a look at some Agda or Unicode-enabled Haskell code to see it really improving readability... though hampering type-ability.

Agda's use of Unicode makes it far less readable to me. Readability is a subjective thing, of course.

Re: Where and When Did the Symbols "+" and "–" Originate?

#77

Post by hcolomb »

rucker wrote: post #52
ghc wrote: post #34

Earlier quoted context omitted.

Similarly, in Japan one pronunciation of 4 is also the word for death, so it's frequently omitted.

This is also true in China (at least in Mandarin-speaking regions, I don't know about Cantonese or other dialects).

Also in Korea because of the Sino-Korean word for 4.

Re: Where and When Did the Symbols "+" and "–" Originate?

#78

Post by xerula »

Retric wrote: post #72
xerula wrote: post #71

Earlier quoted context omitted.

Our yardstick is pretty good. We have characterized a vast range of the objects we share out universe with in immense structural detail, from lifeforms here on earth to astronomical objects billions of light years away. The human brain sticks out. I wrote my comment precisely because it has become a cliché to say what you're saying – how small, ignorant and insignificant we are in relation to the universe, how we com…

We know a lot about a tiny area, and a tiny amount about a large area. But, suggesting we know anything about life / AI outside our solar system is pure hubris.

The universe presents overwhelmingly as a vast void. Of the total space in the universe, what fraction at most do you think is occupied by self-aware minds? What is the maximum percentage of all the matter in the universe that is organized into conscious beings? Regardless of whether life is common or rare on other planets, it is certainly vanishingly scarce overall.

Re: Where and When Did the Symbols "+" and "–" Originate?

#79

Post by oftenwrong »

rucker wrote: post #52
ghc wrote: post #34

Earlier quoted context omitted.

Similarly, in Japan one pronunciation of 4 is also the word for death, so it's frequently omitted.

This is also true in China (at least in Mandarin-speaking regions, I don't know about Cantonese or other dialects).

The Japanese pronunciation in question is the Chinese-derived pronunciation for both 四 and 死.

Re: Where and When Did the Symbols "+" and "–" Originate?

#80

Post by Retric »

xerula wrote: post #78
Retric wrote: post #72

Earlier quoted context omitted.

We know a lot about a tiny area, and a tiny amount about a large area. But, suggesting we know anything about life / AI outside our solar system is pure hubris.

The universe presents overwhelmingly as a vast void. Of the total space in the universe, what fraction at most do you think is occupied by self-aware minds? What is the maximum percentage of all the matter in the universe that is organized into conscious beings? Regardless of whether life is common or rare on other planets, it is certainly vanishingly scarce overall.

Of the total space in the universe, what fraction at most do you think is occupied by self-aware minds?

Somewhere between vary close to 0% and vary close to 100%.

What is the maximum percentage of all the matter in the universe that is organized into conscious beings?

Somewhere between vary close to 0% and vary close to 100%.

Regardless of whether life is common or rare on other planets, it is certainly vanishingly scarce overall.

That makes plenty of rather large assumptions life may or may not only consisting of organic life on planets. For example, as our view of the universe is hobbled by the speed of light most of the planets in existence may have been transformed into Dyson spheres by AI (as one possibility) and we have no way of knowing. Or to bring up a classic idea the observable universe may be an influentially small part of a larger organism.

PS: Now, I suspect your probably more or less correct. However, just because something seems to be the most likely possibility does not make it the only option.

Post reply on HN