I have two independent chapters. I want to override the chapter numbering. So for example, a theorem 7 in section 3 in chapter 2 is labeled as 2.3.7. How could I get only the label 3.7?.
Remove the recursive section numbering (that is,
\thetheorem by adding
to your preamble.
Unless stated otherwise, this will still leave sections to be reset with every new chapter. As such, you might end up with two theorems numbered 3.7, say.