I'm writing a small and simple paper to finish my graduation, I never wrote or published anything before. Is about some irrational/transcendental numbers. I was mentioning some numbers that it's not know to be irrational or not, famous ones are: $e\pi, e+\pi$ and other not so famous like $\ln \pi, e^e, \pi^\pi$. So I was looking where I could find a reference to these statements. And I found on arXiv [Some transcendence results from a harmless irrationality theorem](https://arxiv.org/abs/1310.7289) that states all that. So I thought: "perfect".


However... on arXiv is also:


[The Product $eπ$ Is Irrational](https://arxiv.org/abs/1706.08394)


[The Zeta Quotient $ζ(3)/π^3$ is Irrational](https://arxiv.org/abs/1906.10618)


Notice that the two papers above are by the same person (I think this person solved so many open problems that Fields Medal should change the $4$ years rule and give him a medal every week). And I found in arXiv, but can't find the link, that *all* odd zeta values are irrational.


Well, one simple way to check if the paper is trustworthy or not is to see if it has been published somewhere. The first link was published, so everything is ok. But, for example, the proof of the weak goldbach conjecture was posted in arXiv but never published anywhere else. From the wikipedia page [Goldbach's weak conjecture](https://en.wikipedia.org/wiki/Goldbach%27s_weak_conjecture) : "In 2013, Harald Helfgott published a proof of Goldbach's weak conjecture. As of 2018, the proof is widely accepted in the mathematics community, but it has not yet been published in a peer-reviewed journal."


So how much can one trust arXiv to use it as a reference? I think there is a lot there that is true, but is also not published somewhere else, like the weak Goldbach conjecture proof. But also a lot there is wrong and obvious not published.


I would appreciate improved tags because I don't know the proper ones. Thanks for the answers! 



How reliable is arXiv to use as a reference in a paper?
In general it is poor scholarly practice to make a final decision about how trustworthy something is solely on the basis of where it appears, whether it's the arXiv or a published journal. As Vladimir Voevodsky eloquently explained some years ago, famous results by famous people in famous journals [can still be wrong](https://www.ias.edu/ideas/2014/voevodsky-origins).


In your case, if all you want a reference for is the fact that some constants are not known to be irrational or transcendental, then presumably nothing important in your paper logically depends on this claim being true, so it does not matter all that much how reliable the reference is. If your claim is wrong, the worst that can happen is that someone will be annoyed that their great paper solving the problem was overlooked by you, or someone might work on a solved problem thinking that it is unsolved. So in my opinion it's fine to cite the arXiv paper in this case.


