I think that the kind of interview you get tells a lot about the person that is interviewing you. I have been interviewed by professors and PhDs, and I have worked with them too, and never they expected anyone to remember some specific knowledge from several years ago. Hell, I spent more than 5 years working on Kalman filters and I don&#x27;t think I could code the algorithm without having a look at wikipedia (I always forget the formula for the &#x27;K&#x27; matrix). I remember taking Udacity&#x27;s course about robotics and when Sebastian Thrunn appeared on the video and said he always forgot the formula too a tear dropped from my eye. If someone makes you that kind of specific technical questions my guess is that they lack enough qualification to better assess you, I don&#x27;t care if they work in Google, Facebook or whatever.