I Removed the term "Glushkovise" where we just mean "epsilon-free".
I'm not comfortable with using the term Glushkov NFA, because that implies using Glushkov's construction, which gives a particular NFA structure from parsing a regex. Not having epislons isn't enough to satisfy that, and I think it's confusing to mix the two things.
Naming about errors; the X means "expected". And unsupported operators are not syntax errors
Two small things here:
Xmeans "expected". And unsupported operators are not syntax errors