# Talk:1381: Margin

Isn't it possible that a mathematician knows about the existance or the proof of something, but doen't know how to technically do it? In this case, the margin remark would be accurate and not so funny. They have found a proof of existance for infinite information compression, but not yet discovered an actual method to do it. 141.101.104.56 05:32, 13 June 2014 (UTC)

Yes, when there's no example, it's called a pure existence theorem. If you actually demonstrate an example, that is a constructive proof. Mattflaschen (talk) 05:38, 13 June 2014 (UTC)
Actually the proof of the Shannon-Hartley theorem is non-constructive. It tells you the data rate of the best possible channel coding, but does not tell you how to achieve it! 108.162.215.47 07:58, 13 June 2014 (UTC)

Setting font-size to 0 would be the same as not printing any information at all, you'll still use the same number of bits and be able to send the text to other computers which can read the information. The Shannon-Hartley theorem is, as far as I can see from the wikipedia article, about analogue channels anyway. --Buggz (talk) 06:16, 13 June 2014 (UTC)

Isn't this also a reference to Jan Sloot's digital compression mechanism where a movie would fit into 8 kbyte? Kaa-ching (talk) 07:36, 13 June 2014 (UTC)

This was my first time editing Explain XKCD, but I fear I may have went too far in replacing the current explanation of the title-text with my own and removing the incomplete tag. Is it OK? YatharthROCK (talk) 08:10, 13 June 2014 (UTC)

I think you title text explain seems fine (I have not checked on the Shannon theorem.) But I think it is too soon to make this explain marked as complete. So I have undone that. Great to have one more to edit the explain so keep up the good work. Kynde (talk) 10:46, 13 June 2014 (UTC)

Is the problem behind Fermat's Last Theorem "deceptively simple" or "deceptively difficult"? I've never quite worked out which way it should be. Unlike "cheap at half the price" which really should be "cheap at twice the price" and the effect of putting in the word "only" into "glass ... half full/empty". But I bet you all could care less (or, more accurately, "couldn't care less", because you already do not care at all), right? ;) 141.101.98.232 11:44, 13 June 2014 (UTC)

I believe the correct wording would be "deceptively difficult". Deceptively simple would imply that the problem looked quite difficult on the surface, but once work had begun it was found to be quite simple. Fermat's last theorem goes the other way. It is simply stated with very few elements, so it would seem the proof should be easily constructed, but is actually quite difficult.