Is my mathematics "folklore" paper worth publishing? I wrote a math paper a while ago which was initially mainly for my own attempt to understand a topic/theorem in algebraic geometry. The methods and results are kind of folklore (not well-documented in literature). Although the ideas presented in my write-up was sketched in a recent and well-known conference report, the details and the proof of the main theorem were not given. My write-up did the job to give a detailed treatment of the theory and gave a proof of the main theorem. So this is kind of something between expository and research (I think?).
Now I'm wondering if this paper is worth to be published?
P.S. The main result was also proved by someone using a different approach and got published in a good journal this year.
I would definitely put it on the arxiv because it could help other people.
Whether it is publishable in a journal is a question which you should probably discuss with other experts in the field.