## How do you end your proofs? QED, box, ...

For the discussion of math. Duh.

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## How do you end your proofs?

QED
87
41%
Open Box
48
23%
Filled In Box
31
15%
WWWWW or W^5
8
4%
Other
39
18%

mudge
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### How do you end your proofs? QED, box, ...

In the vein of W^5 (or WWWWW = "Which Was What We Wanted") I'm trying to get "BB" popularized.

Seriously, next time you're telling somebody a proof, when you get to the end, just say "badabing" .. it fits so well.
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LoopQuantumGravity
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### Re: How do you end your proofs? QED, box, ...

mudge wrote:In the vein of W^5 (or WWWWW = "Which Was What We Wanted") I'm trying to get "BB" popularized.

Seriously, next time you're telling somebody a proof, when you get to the end, just say "badabing" .. it fits so well.

THE END

I also like to start proofs with "BEHOLD!"
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mudge
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### Re: How do you end your proofs? QED, box, ...

LoopQuantumGravity wrote:
mudge wrote:In the vein of W^5 (or WWWWW = "Which Was What We Wanted") I'm trying to get "BB" popularized.

Seriously, next time you're telling somebody a proof, when you get to the end, just say "badabing" .. it fits so well.

THE END

I also like to start proofs with "BEHOLD!"

haha, nice.

For the really avant garde proofs, do you end with FIN?
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Robin S
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### Re: How do you end your proofs? QED, box, ...

Quite surprised that QED is so unpopular (so far).
This is a placeholder until I think of something more creative to put here.

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### Re: How do you end your proofs? QED, box, ...

QED is by far the coolest.
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### Re: How do you end your proofs? QED, box, ...

"Ok, tea time!"

(Mathematics is thirsty work.)
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### Re: How do you end your proofs? QED, box, ...

Gelsamel wrote:QED is by far the coolest.

Word.

What's even better is when you use QEF, and people are like WTF?.
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### Re: How do you end your proofs? QED, box, ...

For me, it depends on the complexity of the proof. QED has an audacious ring to it, and is constricted to 'surprising' proofs, i.e. proofs which depend on a property that is seemingly unrelated to the claim; and, I'd guess, new proofs, but I haven't written any of them.

For simple, straight-forward proofs, an open box suffices.

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### Re: How do you end your proofs? QED, box, ...

I use QED.

Edit: I also like to preface that with voilá if the proof involved a surprising step, especially to finish.

So if it's something that is non-obvious until the very end, follow the key point with "And voilá!, [last few lines]. QED"
Last edited by xyzzy on Mon Oct 29, 2007 6:01 pm UTC, edited 1 time in total.
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### Re: How do you end your proofs? QED, box, ...

For someone who will happily admit that I struggle at maths and often have to work up a good brain sweat before reaching the end of a problem , QED is the sweet relief and the knowledge of a job well done.
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### Re: How do you end your proofs? QED, box, ...

TYFC

Actually...I just use a box, or random scribble.
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### Re: How do you end your proofs? QED, box, ...

Normally just a box, but if it's something difficult or something amazingly cool (eg. seemingly unrelated stuff with a awesome surprise twist at the end) QED is the perfect way to end it with a bang. QED, bitches.
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Amicitia
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### Re: How do you end your proofs? QED, box, ...

I light the proof on fire when it's finished.

Or I use a clock-stamp for start and finish. Thank you very much LaTeX.
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antonfire
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### Re: How do you end your proofs? QED, box, ...

Usually, I don't really put anything. Sometimes a box. For the particularly special ones, I write "Proven With No Enduring Doubt".
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### Re: How do you end your proofs? QED, box, ...

Granted I'm still an undergrad, so my proofs haven't been difficult or surprising. However, I put a diagonally hashed box at the end. If it's a iff problem, I'll put a half filled diagonally hashed box at the end of each if-then statement and then state my conclusion and follow it with a hashed box.

uselessuser
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### Re: How do you end your proofs? QED, box, ...

I mostly use boxes. Simple, boring boxes. They always seemed to yell "and if you consider _this_ proof completely random and weird, wait until I you see the one where I left out the few remaining english words as well!". Payback time.

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### Re: How do you end your proofs? QED, box, ...

Open boxes ftw! I'm surprised QED is so popular. It's not common in books.

of.hippo
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### Re: How do you end your proofs? QED, box, ...

I usually just do a filled in box, but I used to write "Ta-Da", then it morphed into a ta-da symbol, which quickly became a TIE Fighter. Please draw Star Wars ships at the end of proofs, it makes professors happy.

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### Re: How do you end your proofs? QED, box, ...

QED...

In huge letters scrawled over the proof itself... with a black marker.
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### Re: How do you end your proofs? QED, box, ...

Although I do like using QED, I actually use an empty box more often. That way I can draw in a smiley face inside it if I get bored. Um, pixel in a smiley face. Hmm I don't think that helped much.

So I can pixel in TIE Fighters!
LOWA

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### Re: How do you end your proofs? QED, box, ...

qed

All lowercase. Although "tea time" and "bada-bing" are both interesting options, and I'll just have to try "Behold!" some time.

For the particularly special ones, I write "Proven With No Enduring Doubt"

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### Re: How do you end your proofs? QED, box, ...

I like the box for it's simplicity, yet it oozes loads of raw prooving power. When you put that box, it MEANS something, and that 'spretty powerful for a little box. Perhaps too much for it to handle.

But, there is nothing quite like scrawling QED over half the page when you finally crack a proof that's had you crying, screaming, and suffering for 3 days straight.

LoopQuantumGravity
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### Re: How do you end your proofs? QED, box, ...

of.hippo wrote:I usually just do a filled in box, but I used to write "Ta-Da", then it morphed into a ta-da symbol, which quickly became a TIE Fighter. Please draw Star Wars ships at the end of proofs, it makes professors happy.

I do occasionally call a capital phi "capital tie fighter."
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### Re: How do you end your proofs? QED, box, ...

QED unless it was a proof by contradiction which gets an "RAA!!!!" for reductio ad absurdum.

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### Re: How do you end your proofs? QED, box, ...

Sometimes a box. For the particularly special ones, I write "Proven With No Enduring Doubt".

I'm definitely doing that next time I have to prove something.

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### Re: How do you end your proofs? QED, box, ...

[quote]have to prove something[/url]

...or something to prove.
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Dongorath
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### Re: How do you end your proofs? QED, box, ...

CQFD (it's French : "Ce qu'il fallait démontrer", roughly translated to "What was to be demonstrated" or whatever a better translation would be).

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### Re: How do you end your proofs? QED, box, ...

I'm a fan of QED in other arenas besides math, like finishing up a section of a debate with "QED, bitch."

Back in discrete math, though, I usually just finished up with a derivative of W^5 (something like "which is as stated"), and then a double slash in/beside the right margin. That's what the teacher used, so I just sort of adopted it, and then kept using it later.

ks_physicist
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### Re: How do you end your proofs? QED, box, ...

I am tagging this purely for future reference.

Unakau
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### Re: How do you end your proofs? QED, box, ...

I like QED. It looks so proffessional.

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### Re: How do you end your proofs? QED, box, ...

I'd like to say I use something cool or inventive ("spla-DOW!"), but I just typically use "QED" or sometimes nothing if it's obvious the proof is done.
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### Re: How do you end your proofs? QED, box, ...

Usually I don't write the proof at all. I just do the math completely out of order through my notebook, in the end it looks like a total mess.

When I'm serious about it though i use c.q.d. at the end of the proof. It's short for como queríamos demonstrar which is Portuguese for the same thing the french-speaking guy posted.

I'm looking foward to use "Ta-Da" or "Behold!" in my tests
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### Re: How do you end your proofs? QED, box, ...

A T.A. of mine suggested ending proofs with "OSB": "Oh snap, bitch."

I use a filled-in box, right-justified. In my notes, I make an empty box instead when the proof is omitted or informal.

Sly Si
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### Re: How do you end your proofs? QED, box, ...

I usually use the filled-in box by default. When I'm in the mood, though, I use QED. Results that have a surprising twist at the end (i.e. going from something seemingly completely unrelated to the exact thing we want to prove in a line or two) usually get an exclamation point, sometimes a box as well. And when the result is nifty, I use a smiley face.

I also use the smiley face in lecture notes to stand in for "and the rest of the steps are obvious".

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### Re: How do you end your proofs? QED, box, ...

"as desired"

I really hate QED. It seems overly pretentious. and also means quantum electrodynamics, so all the mathematical physicists get confused.

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### Re: How do you end your proofs? QED, box, ...

My ACalc professor used a lightning bolt to conclude a proof by contradiction, which I thought was way better than the alternative of ><. When I saw that, though, I wished other proofs had a cool symbol, so I started using a really small tornado, complete with house and Todo for my other proofs. If I get a chance, I'll draw it up in GIMP later and attached it.

Also, my Algebra prof would use a box for proofs, and it would be filled in if all details were provided, something that looked like a mesh if it was mostly there but there were some things missing, and an empty box for a sketch.

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### Re: How do you end your proofs? QED, box, ...

MysticTerminator wrote:I really hate QED. It seems overly pretentious.
In an effort to become more pretentious I am adopting CQFD instead of QED.

Although having a thing for full sentences and clarity in my writing most of the time I end with "So [thing that I was proving] must hold."

Maurog
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### Re: How do you end your proofs? QED, box, ...

I always thought the box was an ancient Latin pun based on Quod Erat sounding similar to the latin word/root for "square". I now know it isn't, but it made so much sense!

And still does. If the ancients thought of it, they'd use it for sure.
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### Re: How do you end your proofs? QED, box, ...

What, "quod erat demonstratum" doesn't mean "Look, a filled-in box"?! XD

I'm seriously tempted to go the lolcat route and go "kthxbai" after proofs (and starting proofs with "I can has <proof method here>," since my current class has instructions like "Prove this by induction" and "Prove this by contradiction".)
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### Re: How do you end your proofs? QED, box, ...

Kawa wrote:What, "quod erat demonstratum" doesn't mean "Look, a filled-in box"?! XD

I'm seriously tempted to go the lolcat route and go "kthxbai" after proofs (and starting proofs with "I can has <proof method here>," since my current class has instructions like "Prove this by induction" and "Prove this by contradiction".)

This rocks.

I would also like to propose "TAFJ", for "That's A Fact, Jack!"