Student or Learner
What does mean "upon improving the..." in the sentence below:
"Upon improving the Born approximation as customarily applied to electron diffraction experiments, Glauber was able to show..."
The easiest way to show you what it means is to say that this could also be written as "When he had improved the Born approximation..." or "After improving the Born ..."
I'm not a teacher of English, but I have spoken it for (almost) all of my life....