First little background. I have master degree in mathematics. Then I decided to continue to study PhD level. After some years I cancel study (reason was in some things in my life). Now I am returning back to mathematics. I have job, but I do mathematics in my free time. Is it possible to publich some article in some journal, if I am not connected to any university or research institute?(I am aware about review process in mathematical journals)
Of course you can. But since you want to publish something maybe it would be better to consider re-entering a PhD program in order to spend more time doing math. There you will have more opportunities to do research and publish your work.