# How to write down proofs?

I'd like to write down proofs. I use first-order logic and natural deduction. Formulas tend to be long, too long for LaTeX. Writing formulas with the computer is also a slow process. Handwriting is a lot faster and more natural, but I can't trust paper. Time, water, dirt, fire are its enemies. I could write down something and then immediately scan it, but I'm an eco-guy and I'm worried about using a whole page for only two lines. How do you write math? Thanks.

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I would like to be able to provide a serious answer to this question, but I find it difficult to conceive of what one might look like. I've downvoted this question because I am inclined to believe others would have similar trouble as the question stands. However do not let this deter you from asking questions in future. –  Tom Boardman Aug 10 '10 at 14:14
I know you guys really like very advanced questions and not basic things as this one, but I'm desperate and I need to know. –  le3 Aug 10 '10 at 14:17
I think that this question should be community wiki and that we should post ways we write down logical expressions. While we all may have different tastes, it would be good to have a list of popular ways so that people who are dissatisfied with their solution (or don't have one!) will know what else is available. –  AndrejaKo Aug 10 '10 at 14:41
Maybe retitling to 'what are some good Tex editors' with some advantages/disadvantages requested for each one answer per question community wiki question would be interesting and productive. As it is the question is just inane. –  Tom Boardman Aug 10 '10 at 16:29
le3, please rewrite your question. As it stands, it's virtually equivalent to "How do I write math? I don't like paper and I don't like computers, what can I do?" which is unanswerable. –  Jamie Banks Aug 10 '10 at 17:47

There are a number of possible approaches. One can become quite proficient even with a text-based editor if it is user extensible - e.g. see the (La)TeX extensions for Emacs. These are easily user customizable if you have basic programming knowledge. Alternatively see the WYSIWYG LaTeX front-ends, e.g. Lyx. Another possibility is to employ a graphics / digitizing tablet (e.g. Wacom) for input, but this may require writing your own software to obtain optimal productivity.

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A tablet would be good, but those with an LCD display are very expensive (about 1,000 euros). –  le3 Aug 10 '10 at 14:35
I've seen tablets (but can't provide source at the moment) which use pens with graphite tips, so you can write on real paper placed between tablet and pen. This makes it easier for people who aren't used to write at tablet and look at computer. –  AndrejaKo Aug 10 '10 at 14:46

If you plan to enter the scientific community you should begin to learn LaTeX at precisely this moment. I recommend text-based editors such as emacs or vim for the sole reason that they are available on every unix-based machine, whether accessed remotely or on your own personal shiny macbook.

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On a blackboard.

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On book margins. Like Fermat did -or didn't.

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Judging from your question, I presume you want to write down formal proofs in natural deduction. If so, a proof assistant (check Wikipedia for examples) will help you.

If you don't care that your proofs are formally checked, you can use $\LaTeX$ with the bussproofs package.

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If you are a user of Windows 7 and have a graphics tablet , you could use it in combination with hand-writing recognition using the Math Input Panel.

It will take some time to train your computer to correctly recognize your handwriting, but if you are only going to use it for formulas, then it shouldn't take more that few days. You can also use it with mouse, but it's less natural then with a real pen and tablet.

Another factor that can impact your experience is the choice of the tablet. Good ones are mainly from Wacom and are expensive (about 50€ here for cheapest models!) but come with good pens and good drivers. They are also powered using EM induction, so the mass distribution in the pen is more like in real pens. (BTW, I really don't want to advertise Wacom, but I'm not aware of any other manufacturer whose tablets have good drivers and whose pens are small and light enough.)

I also used a tablet made by Trust and had problems with drivers and weight distribution. Pen is powered by 2 AAA batteries which are in top part of the pen making it very heavy. Also pen is larger that a real pen so it feels clumsy.

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