Correct negative form of punctual verbs

Question

Take the verb 座る. As a punctual verb, it appears as 座っている when describing a person who "has sat down and remains sitting." When using the negative, there are two options: 座らない and 座っていない.

Given the question, "Is Tom the guy who is seated?" and the response "Tom is not sitting, he's the guy doing jumping jacks", which form of the negative matches the intended meaning? What would the other form mean?

This question was prompted by learning that the appropriate negative of 知っている is 知らない, and none of my learning resources describe anything about 〜ている forms in the negative.

Answer 1

「座らない」 expresses a feeling of "I'm not going to seat", it talks about the future volition. If you say something like 「座らない人」, you mean the person who won't seat there, talking about future.

「座っていない」 is the negative form of 「座っている」, which talks about the state, if it's seated or not, or if someone is seating or not. As for your question, you should use 「座っていない」 and 「座っている」, because you want to talk about the state, not one's willing to do something.

Is Tom the guy who is seated?

might be translated to:

座っているのはトム？

If you just say:

座らない。

You are coldly saying:

I'm never gonna seat there.
There's no way I'll seat there.