I need a GUI on a remote server to which I have an ssh connection. Is it possible to share my X11 window system with it given that there's no X11 installed on the server?
If the remote application is normal, then when it was installed, it would have pulled in all the necessary X11 components for it to run, so when you redirected the display back to your local machine, it would actually be using much of the X11 system on the remote machine.
In your case, in the comments, you mention that this is a GUI installer, so it's expecting to be run on a system which already has X11 installed and it just makes use of it. So if X11 is not installed on the remote system, it will just fail.
Of course, if the GUI installer provides all the necessary X11 libraries itself, then the