What are some notable (famous?) instances where the following has occurred.
A particular author proves:
Every P which satisfies Q has property Z.
A few years later (roughly speaking) the same author proves:
Every P has property Z;
thus rendering at least part of their original research article obsolete.
Is such a thing common?
On one hand, the author should be the person most equipped to strengthen their result since they likely tried before, learned some traps to avoid, and got a partial solution.
On the other hand, the author could prefer not to revisit their work to avoid duplication & making their own work obsolete, or simply to do research on different things they find interesting. Maybe they eventually just "quarantine" the problem in order to make better use of their time and mental energy.
On a personal level, I really struggle with "letting a problem go", especially if it's one I've previously solved certain cases of.
