Question about ITTEIMASU
 

Hi my friends, as you see I'm new here :)

And have a question to ask.
So I'm wondering, if itteimasu means "have gone" or "is going" because everyone tells me something different.

Some say: itteimasu can "only" be "is going"
Others say: itteimasu can be both
And then others say the opposite

Im desperate...

The problem is that "have gone" has a wide range in time space, thus I agree it can mean both or it can mean only one.
I would study the uses of -teiru and understand when they are used instead of trying to translate them in English.

I think for motion verbs like 行く、来る etc. when said as 行っている or 来ている for example (I don't know the technical terms so bare with me here)
Is like saying "went and is there now" or something along those lines

So for example:
彼は図書館に行っている - He went to the library and is there now.

I think it's the same with all motion verbs like 来る、帰る etc.

Perhaps somebody else will be able to explain in more technical terms than I can and if I am wrong then I would like to see somebody else explain, otherwise I would have had the wrong idea for a while now. :p

Thx for the answers

You mean Present Perfect Simple? When a past action has effect on the present?

That is why i don't know any technical terms lol, the words Present Perfect Simple just went straight over my head xD

But if you can say ikimashita, which means "I went", it would be the same wouldnt it?

The way I think of it is this:

彼は図書館に行っている
He went to the library and is there now(or will be there maybe?)
so the action was completed and he is existing there now being the いる

彼は図書館に行った
He went to the library
Doesn't necessarily mean that he is there currently

Again this is just how I think of it so I could well be wrong since i haven't used it much before, but this is how I have thought of it for a long time now.

Did Mom go to the grocery store?

はい、行きました。 [Yes she went, and the implication is that she is already done and home.]

はい、行っています。[Yes she left, and the implication is that trip is not finished, so she still there now.]

Ok I also thought that way, thx.

The fact is that the same difference you have it in English. He went to the library and he has gone to the library.
Unfortunately "have done" form in English has a wider ranger of meanings and some of them is not represented with -teiru. For example the present perfect can be used to give an idea of an experience had sometime in the past (have been to Japan, have gone to that restaurant before...) and in this case in Japanese you will use another way of saying the same thing.
In the same way the -teiru form is used to express ideas that the present perfect won't. For example you can use the -teiru form to give an idea of an action done more times as a habit, thing that you would show in English with the simple present.

That is why many people give you different answers to your questions. They can mean the same thing, but they cannot.