# "Therefore" sign **URL:** \ **Category:** Factual Questions\ **Created:** [September 15, 2000, 6:20pm UTC](https://boards.straightdope.com/t/therefore-sign/33336 "2000-09-15T18:20:07Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![amarinth](https://avatars.discourse-cdn.com/v4/letter/a/3be4f8/32.png) [@amarinth](https://boards.straightdope.com/u/amarinth)\ **Post date:** [September 15, 2000, 6:20pm UTC](https://boards.straightdope.com/t/therefore-sign/33336/1 "2000-09-15T18:20:07Z")
I was asked this several days ago, and I couldn’t find an answer, and its been bugging me ever since. As I’m sure you know, in mathematical proofs (and other places) three dots arranged in a triangle pointing up is read “therefore.” Is there a name for that punctuation/symbol/shorthand? Is it just the therefore sign? ---
**Author:** ![Celyn](https://avatars.discourse-cdn.com/v4/letter/c/9dc877/32.png) [@Celyn](https://boards.straightdope.com/u/Celyn)\ **Post date:** [September 15, 2000, 6:25pm UTC](https://boards.straightdope.com/t/therefore-sign/33336/2 "2000-09-15T18:25:32Z")
Hello, Amarinth, nice to meet you, although I wish I hadn’t read your question! It hadnt’t occurred to me before, but I don’t know a name for it either, and it’s going to bug me now. Nor do I know a name for the same symbol reversed - I hope someone clever knows both, because I can see it would be a really difficult thing to look up anywhere. ---
**Author:** ![AWB](https://avatars.discourse-cdn.com/v4/letter/a/bb73d2/32.png) [@AWB](https://boards.straightdope.com/u/AWB)\ **Post date:** [September 15, 2000, 6:26pm UTC](https://boards.straightdope.com/t/therefore-sign/33336/3 "2000-09-15T18:26:53Z")
My Mathematics Dictionary says it means therefore or hence. But no name specifically. “Hence Sign” is shorter, but sounds funny. (“ensign”? “head sign”?) ---
**Author:** ![stuyguy](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@stuyguy](https://boards.straightdope.com/u/stuyguy)\ **Post date:** [September 15, 2000, 6:38pm UTC](https://boards.straightdope.com/t/therefore-sign/33336/4 "2000-09-15T18:38:14Z")
I’ll just second AWB’s post. My type/copy editing reference sources call it a “therefore” or “hence” sign. The reverse (triange of dots, pointing down) is simply the “because” sign. ---
**Author:** ![Keeve](https://avatars.discourse-cdn.com/v4/letter/k/f07891/32.png) [@Keeve](https://boards.straightdope.com/u/Keeve)\ **Post date:** [September 15, 2000, 7:40pm UTC](https://boards.straightdope.com/t/therefore-sign/33336/5 "2000-09-15T19:40:58Z")
No, it doesn’t seem to have a name. Check it out at [Symbols.com](http://Symbols.com) – [http://www.symbols.com/encyclopedia/44/441.html](http://www.symbols.com/encyclopedia/44/441.html) ---
**Author:** ![Kyberneticist](https://avatars.discourse-cdn.com/v4/letter/k/dc4da7/32.png) [@Kyberneticist](https://boards.straightdope.com/u/Kyberneticist)\ **Post date:** [September 15, 2000, 7:49pm UTC](https://boards.straightdope.com/t/therefore-sign/33336/6 "2000-09-15T19:49:05Z")
Hm. Symbolically speaking, how is: ```auto \ . ------\ . . different then ------/ / ``` Crudely drawn if-then. (to be distinguished from) ```auto / \ /---------\ \---------/ \ / ``` ---
**Author:** ![Sith\_Sheriff\_Brody](https://avatars.discourse-cdn.com/v4/letter/s/a6a055/32.png) [@Sith\_Sheriff\_Brody](https://boards.straightdope.com/u/Sith_Sheriff_Brody)\ **Post date:** [September 16, 2000, 11:10pm UTC](https://boards.straightdope.com/t/therefore-sign/33336/7 "2000-09-16T23:10:33Z")
To the best of my knowledge, “Therefore” is used in mathematical formulas and proofs, and the arrow-thing (“Yields”?) is used in chemical equations. -SSB ---
**Author:** ![TheNerd](https://avatars.discourse-cdn.com/v4/letter/t/858c86/32.png) [@TheNerd](https://boards.straightdope.com/u/TheNerd)\ **Post date:** [September 17, 2000, 12:25am UTC](https://boards.straightdope.com/t/therefore-sign/33336/8 "2000-09-17T00:25:06Z")
=\> is a logical operator. ```auto . . . ``` is used in proofs and theorems, usually in the conclusion. Sorry about the formatting. ---
**Author:** ![Wanderlust](https://avatars.discourse-cdn.com/v4/letter/w/9fc29f/32.png) [@Wanderlust](https://boards.straightdope.com/u/Wanderlust)\ **Post date:** [September 17, 2000, 12:57am UTC](https://boards.straightdope.com/t/therefore-sign/33336/9 "2000-09-17T00:57:20Z")
This is your chance at collecting the 15 minutes Andy Worhol envisioned. Name the symbol and create a website with that name to promote its use. Don’t be shy because you aren’t a famous mathematician. America was not named by Columbus the discover, but by a mapmaker that saw a blank spot where a name should be. ---
**Author:** ![Kyberneticist](https://avatars.discourse-cdn.com/v4/letter/k/dc4da7/32.png) [@Kyberneticist](https://boards.straightdope.com/u/Kyberneticist)\ **Post date:** [September 17, 2000, 1:53am UTC](https://boards.straightdope.com/t/therefore-sign/33336/10 "2000-09-17T01:53:36Z")
> [@](#): > > \*Originally posted by TheNerd \* > \*\*=\> is a logical operator. > > ```auto > > . > . . > > ``` > > is used in proofs and theorems, usually in the conclusion. > Sorry about the formatting.\*\* ## Yeah, I’m using it a lot in number theory. It is: A|B|=\> 1|1|1 0|1|0 1|0|0 0|0|1 But the definition of what those two symbols “mean” seems the same essentially, I’m wondering if I can start doing: ```auto . A . . B ``` In number theory and comp. sci. boolean arithmetic proofs, just to be cute, or if the three dots are only allowed to indicate a finaly conclusion (sorta like the annoying use of Q.E.D.). ---
**Author:** ![Kyberneticist](https://avatars.discourse-cdn.com/v4/letter/k/dc4da7/32.png) [@Kyberneticist](https://boards.straightdope.com/u/Kyberneticist)\ **Post date:** [September 17, 2000, 1:55am UTC](https://boards.straightdope.com/t/therefore-sign/33336/11 "2000-09-17T01:55:28Z")
It’s always when you type it out and submit it that you notice that you changed =\> to \<=\> by screwing up the 1s and 0s _quiet sobs_ I have got to start using preview… ---
**Author:** ![Damhna](https://avatars.discourse-cdn.com/v4/letter/d/3bc359/32.png) [@Damhna](https://boards.straightdope.com/u/Damhna)\ **Post date:** [September 17, 2000, 11:10am UTC](https://boards.straightdope.com/t/therefore-sign/33336/12 "2000-09-17T11:10:27Z")
Isnt there also a symbol that is the reverse? The triangle upsidedown to indicate “because” or something similar?