What does the publisher mean by “Manuscripts […] are not returned to the authors”? I submitted a paper to the journal Mathematica on January this year, but I haven’t heard anything from them so far. I tried to write to the editorial office a few days ago, but did not receive any answer.
Then I noticed the following sentence on the web page of the journal, in Information for authors:

Manuscripts not accepted for publication are not returned to the authors.

Could someone explain me its meaning? I thought that, even in case of rejection, at some point they would let me know. Does this sentence mean that this is not the case?
Back in the Olden Days, to submit a paper you would mail a hard copy to them. This notice says that they will not mail it back to you; they will only send you a letter with their decision. But nowadays, when we do things by the internet, this notice is largely an anachronism. However this journal does say it still can accept submissions also by ordinary mail.
Assuming you submitted your paper by Internet, I expect you will receive a decision on publication by email in due course.
As a mathematician, I always wait at least 6 months before I inquire about a paper I have submitted.