This question can be seen as falling under proof-verification, whose tag-wiki also mentions improvements; possibly proof-writing is also relevant. It can thus be considered as in principle on-topic.
However, it is important to make sure that the question is not "too broad" or too big a demand. If the proof is a few paragraphs long, this can be a reasonable question; if you link to a twenty page pdf somewhere, this might not go over so well.
Moreover, try to be as specific as possible regarding what type of improvements you are looking for.