I'm in a situation that I've never faced before: I believe that I've found the solution to a classical mathematical problem and would like to get the solution published in a reputed journal. The solution might be wrong as and I'm willing to accept that because I've not shared the solution with anyone yet, but if it is correct (which I hope), it is good enough to be presented in a good journal.
The problem: I want to pursue my masters next year. I'm not a prodigy; hence I've applied to a few good universities but not to the top ones. The journal that I seek to publish my paper in takes 14–18 months on average to accept and a similar time to publish it. Hence, if I want my research outcome to help me apply in some top universities, I'll have to wait that long, hoping my paper gets accepted and published.
I'm a bit protective about my work and wanted to share it with the reviewers of the journal only, but then I got to know about arXiv, where I can publish my paper and it will be visible to everyone. The journal I seek to publish in accepts arXiv-published papers, so that should not be a problem.
Can you please suggest if it is advisable to publish a paper with a potential solution to a classical problem openly on arXiv and then use the arXiv link to share my paper and convince the selection committees about by candidacy?
Is there any other solution to this problem that you'd recommend? This is first time I'm going to publish a paper.