[swhipple]

Possibly, however I don't think you can get much clearer without sacrificing generality.

A terminal emulator and a child process will have different virtual address spaces, so you may choose that as the discriminating factor. A web browser and a web application will share address space. But a web browser and a web application are clearly two separate programs as well.

It isn't really a problem unique to the GPL. Any interpretation of a non-trivial license with conditions will have an element of "I know it when I see it". Software licenses especially due to the level of abstraction.