I was navigating the Graduate Journal of Mathematics, which is a comparatively new peer-reviewed mathematics journal. In its mission-statement, the journal mentions that it takes inspiration from a similar journal that was discontinued in 2000: Le Journal des Elèves de l’Ecole Normale Supérieure de Lyon. There are lots of published articles from this journal, but it is closed now.
There are there other mathematics journals which were also discontinued at a certain stage. For example, LMS Journal of Computation and Mathematics was discontinued in 2015. I guess there are other journals in all subjects which are later discontinued and maybe later some new journals evolve from them just like the mentioned Graduate Journal of Mathematics.
My main motivation for the above questions is the following:
Suppose someone publishes an article in a journal and later the journal gets closed. How would people evaluate the work from a journal which is closed? I know the work will remain valid as long as there is no error in the article. But, would people acknowledge the work equally even after the journals is discontinued?
Especially, in some countries, a Ph.D. degree is awarded on the basis of articles published in a journal. Suppose, this journal is later discontinued. Should the author worry about their Ph.D. award even if the journal gets closed, provided their research work is valid?