Science Math Notation

[Chris Peterson]

Chris, I'm glad to know about ALT-0183. Is there a good reference to non-keyboard symbol codes?

Assuming you are using Windows, run the Character Map utility. By default I think it's under accessories, but just typing "charmap" in the run box will bring it up. The standard fonts like Arial will have all the most common Unicode characters. Find the one you want, click on it, and the ALT code will be presented in the lower right. Just remember that you need to use all four numbers, and you have to use them off your numeric keypad, not the numbers across the top. Go figure. If your keyboard doesn't have a numeric pad, you can always copy the character directly from Character Map and paste it into your browser.

[geckzilla]

http://unicode-table.com/ is fun, too.

[owlice]

What shows up on my computer:

Screen shot 2014-06-01 at 10.49.28 AM.png (10.31 KiB) Viewed 1011 times

[geckzilla]

I'm sorry for that. You are missing out on some good unicode characters. That one is a snowman.

[owlice]

I can see him there, but cannot see him here.
(I can see him in the somewhere, I can see him over there;
I can't see him sitting here, and can't see him everywhere.)

[Chris Peterson]

What shows up on my computer:

Screen shot 2014-06-01 at 10.49.28 AM.png

Probably something to do with how your browser or your OS handles fonts. What's your setup?

[Nitpicker]

The snowman looks to have an unusual colon.

(This discussion of dots has dug up an old memory of when I first learnt about decimal points in primary/elementary school. I was taught to write decimal points as middle dots. Then a few years later we were told to move the decimal points down, and that we could sometimes use a middle dot for multiplication. It is probably no wonder I find them rather interchangeable and not at all jarring. But I concede I am in the wrong and that the official SI Brochure makes no exceptions, unlike the [strange] Wikipedia article. I still think there is room for the SI committee to relax their rules, or for a middle dot to be provided on a numeric keypad, rather than requiring a key-binding five times more time consuming.)

[Ann]

An aside: Here in Sweden, we don't use decimal points, but decimal commas. So using Swedish notation, you would write that the distance to Alpha Centauri from the Sun is 4,2 light-years. We even say "four comma two" light-years. (Or "fyra komma två ljusår".)

We might use the point or dot - what do you actually call that little thing? - but not to show decimals. It is possible to write a million as 100.000.000.

And of course, we say "miljard" when we mean "a billion" and "biljon" when we mean "a trillion" and "biljard" when we mean "a quadrillion". It is probably easier to just count the number of zeros.

Ann

[Nitpicker]

An aside: Here in Sweden, we don't use decimal points, but decimal commas. So using Swedish notation, you would write that the distance to Alpha Centauri from the Sun is 4,2 light-years. We even say "four comma two" light-years. (Or "fyra komma två ljusår".)

We might use the point or dot - what do you actually call that little thing? - but not to show decimals. It is possible to write a million as 100.000.000.

And of course, we say "miljard" when we mean "a billion" and "biljon" when we mean "a trillion" and "biljard" when we mean "a quadrillion". It is probably easier to just count the number of zeros.

Ann

Yes, modern European conventions certainly do make things even more confusing. But I think a million (to two decimal places) would be 1.000.000,00 (or 1 000 000,00) in the "European" convention and 1,000,000.00 (or 1 000 000.00) in the "US" convention.

In English, the number 1.2 would be spoken universally as "one point two", equivalent to one and two tenths.

To add yet more confusion, the "long scale" billion is a "million million", whereas the "short scale" billion is a "thousand million". See: http://en.wikipedia.org/wiki/Long_and_short_scales. No wonder scientific notation is favoured in technical and international fields.

[Ann]

A quick question here. In Swedish, this very small sign, ".", is always called "punkt", regardless of context. In English-speaking countries,you use "point", "dot" and "full stop", and they are hardly interchangeable. I'd appreciate a quick lesson here!

Ann

[Chris Peterson]

A quick question here. In Swedish, this very small sign, ".", is always called "punkt", regardless of context. In English-speaking countries,you use "point", "dot" and "full stop", and they are hardly interchangeable. I'd appreciate a quick lesson here!

Nobody in the U.S. would use "full stop". It's British usage, and I think it's fading out. "Dot" would be rare in America, mostly used in constructions like "you could fit a thousand bacteria on the dot at the end of this sentence." We almost always use "period" when talking about grammatical punctuation, and "point" when talking about numbers (short for "decimal point").

The glyph used for the multiply and cross-product operation is called a "middle dot" or "centered dot". It's also called an "interpunct", but only in the context of grammatical usage, mainly in Latin.

[Beyond]

I call it a period. IF it was up higher, about like this -, I'd call it a dot.

[Chris Peterson]

An aside: Here in Sweden, we don't use decimal points, but decimal commas. So using Swedish notation, you would write that the distance to Alpha Centauri from the Sun is 4,2 light-years. We even say "four comma two" light-years. (Or "fyra komma två ljusår".)

We might use the point or dot - what do you actually call that little thing? - but not to show decimals. It is possible to write a million as 100.000.000.

The SI system allows the decimal separator to be either a comma or a period, to satisfy both sides of the pond. But to avoid further confusion, it explicitly disallows using either to separate groups of numerals. Long numbers are broken into groups of three using spaces, or better yet, thin spaces.

[Nitpicker]

Not a quick answer, I'm afraid ...

A full stop (British, and not fading at all) or period (US) is a baseline dot at the end of a sentence.

A decimal point is also a baseline dot which separates the whole and fractional parts of a number.

Abbreviations and initialisms are indicated with a baseline dot suffix, although this appears to be becoming less fashionable.

Baseline dots are also used as separators in email, web and IP addresses, file names, programming structures, etc.

A dot, as a stand-alone character, may be a baseline dot, a middle dot or an upper dot, the latter two being used a lot in mathematical contexts, and others.

The original spacing between words in ancient Latin or Greek (can't remember which, or both) was noted with a middle dot, also known as an interpunct.

[Nitpicker]

An aside: Here in Sweden, we don't use decimal points, but decimal commas. So using Swedish notation, you would write that the distance to Alpha Centauri from the Sun is 4,2 light-years. We even say "four comma two" light-years. (Or "fyra komma två ljusår".)

We might use the point or dot - what do you actually call that little thing? - but not to show decimals. It is possible to write a million as 100.000.000.

The SI system allows the decimal separator to be either a comma or a period, to satisfy both sides of the pond. But to avoid further confusion, it explicitly disallows using either to separate groups of numerals. Long numbers are broken into groups of three using spaces, or better yet, thin spaces.

That is perfectly true, but SI standards conflict with common/commercial "standards", so the use of non-space grouping-separators for numerals, is still rife.

[Chris Peterson]

That is perfectly true, but SI standards conflict with common/commercial "standards", so the use of non-space grouping-separators for numerals, is still rife.

It is, but fortunately it is rare in scientific publications.

(It's a bit of a nightmare for programmers, too. Operating systems are supposed to be locale aware and deal with things like commas and points automatically, but none quite do, so user interface code that accepts numbers is frequently full of special handlers, and even so is a common source of bugs.)

[Nitpicker]

That is perfectly true, but SI standards conflict with common/commercial "standards", so the use of non-space grouping-separators for numerals, is still rife.

It is, but fortunately it is rare in scientific publications.

(It's a bit of a nightmare for programmers, too. Operating systems are supposed to be locale aware and deal with things like commas and points automatically, but none quite do, so user interface code that accepts numbers is frequently full of special handlers, and even so is a common source of bugs.)

Yep, I'm glad I write engineering software, which for floating point arithmetic, supports not much other that decimal points and exponent notation in double precision. The term "garbage in, garbage out" could be applied to all software, but seems to be used a lot in technical software.

[Nitpicker]

By the way, these American phrases tend to cause smirks and/or raised eyebrows in Australia:

1) "I'm in a bad mood, period."

2) "I'm Randy and I'm rooting for the Reds."

3) "I fell down and hurt my fanny."

If you don't know why, PM me for an explanation.

(Mind you, if I made a mistake, I might compound it by asking an American for a rubber, instead of an eraser.)

[Nitpicker]

"Dot" would be rare in America, mostly used in constructions like "you could fit a thousand bacteria on the dot at the end of this sentence." We almost always use "period" when talking about grammatical punctuation, and "point" when talking about numbers (short for "decimal point").

The glyph used for the multiply and cross-product operation is called a "middle dot" or "centered dot". It's also called an "interpunct", but only in the context of grammatical usage, mainly in Latin.

In English, the word "dot" is used frequently and universally in computer parlance, as a separator.

The "middle dot" is known as a dot-operator when denoting multiplication or (in vector notation) a dot-product.

The glyph "×" is known as a cross-operator when denoting multiplication or (in vector notation) a cross-product.

[geckzilla]

No one I know calls their butt a fanny. We do definitely still use the word "fanny pack" though.

[Chris Peterson]

No one I know calls their butt a fanny. We do definitely still use the word "fanny pack" though.

Of course, in British (and apparently Aussie) English, your fanny isn't your butt.

[Nitpicker]

No one I know calls their butt a fanny. We do definitely still use the word "fanny pack" though.

The first time I heard the term "fanny pack", I had no idea it was a bum bag and felt I'd been given too much information. Whatever they're called, they're ugly and should be relegated to the dustbin of fashion history. [grumpy old man emoticon]

[Nitpicker]

I note that in updated editions of Enid Blyton's The Faraway Tree series, Dick and Fanny have become Rick and Frannie.

[Chris Peterson]

In English, the word "dot" is used frequently and universally in computer parlance, as a separator.

True, that's a different category of usage I wasn't considering.

The "middle dot" is known as a dot-operator when denoting multiplication or (in vector notation) a dot-product.

The glyph "×" is known as a cross-operator when denoting multiplication or (in vector notation) a cross-product.

Here, it can get a little confusing. There's no glyph called "dot-operator" or "dot-product"; those are the mathematical operator names, but the glyph is called the middle dot (or centered dot). There's no glyph called "vector product" or "cross product"; those are the mathematical operator names, but the glyph is called the "multiplication sign" or "times sign" (not the same as a lowercase x, although that is often used as a substitute).

In other words, the glyphs are overloaded; there tend to be more names for their functions than for the actual characters.

[Nitpicker]

In English, the word "dot" is used frequently and universally in computer parlance, as a separator.

True, that's a different category of usage I wasn't considering.

The "middle dot" is known as a dot-operator when denoting multiplication or (in vector notation) a dot-product.

The glyph "×" is known as a cross-operator when denoting multiplication or (in vector notation) a cross-product.

Here, it can get a little confusing. There's no glyph called "dot-operator" or "dot-product"; those are the mathematical operator names, but the glyph is called the middle dot (or centered dot). There's no glyph called "vector product" or "cross product"; those are the mathematical operator names, but the glyph is called the "multiplication sign" or "times sign" (not the same as a lowercase x, although that is often used as a substitute).

In other words, the glyphs are overloaded; there tend to be more names for their functions than for the actual characters.

Are the glyph names perfectly standardised and agreed upon? I thought the glyph names themselves were overloaded.

The dot-operator is just one of the names I would give to the glyphs like "·" (Alt+0183) and "•" (Alt+0149). Other names include: interpunct, middle dot, centre dot, bullet, times, multiplied by.

The cross-operator is just one of the names I would give to the glyph "×" (Alt+0215). Other names include: times sign, multiplication sign.

But I would call neither the dot (scalar) product, nor the cross (vector) product a glyph. They are vector operations, rather than operators. (Picky, picky.)