Recalling standard results in a master's thesis appendix for reader's convenience and/or self-containedness Currently working on my master's thesis, I know that I have to consider that I am writing for an appropriate audience, that is, I write for people who have at least a bachelor's degree in my field (mathematics).

However, I need to use standard results that one learns in third year (in my institution, at least). In particular, these results can be found in any "basic" textbook in the field my work is lying in.

I face a particular dilemma: either just citing the name of the theorem when I use it in the main work without giving any reference, or rewriting the theorem in the Appendix for the reader's convenience (with appropriate reference to a "basic" textbook).

Of course, my supervisors will know these results, but my peers may not remember them and a master's thesis is often expected to be self-contained. I don't expect many people to read my work, of course, but still, I want it to be as "perfect" as possible.

This question is related but it seems the OP is speaking about a basic theoretical concept they would briefly discuss in the main work. Precisely, it would not belong in the appendix, which makes the question different as I am not discussing these basic results: I just use them.

Question: is it acceptable to rewrite classical, basic results in the appendix section of a master's thesis and citing basic reference works about these results for the reader's convenience and/or for the work to be as self-contained as possible?

I shall of course ask this question to my advisor but I wanted to have different advices from professionals on this.
My answer is very similar to the one I gave to the question I linked to in a comment:  There is usually no reason not to include something in a thesis.  Your thesis is a place for you to give a coherent account related to your work on a topic.  There are (usually) no page restrictions, and it should serve as a reference document for future readers.

Many theses include a lot of review material, beyond just what might be contained in a literature survey. A thesis has to contain new material, of course, but it does not all need to be novel, and there can be a lot of merit in giving detailed explanations of known results, if the readers are not necessarily going to be familiar with them in detail.