that is correct, however that's not exactly what the person in question was looking for while interviewing (not for the other person know have knowledge about t

that is correct, however that's not exactly what the person in question was looking for while interviewing (not for the other person know have knowledge about the subject) but the ability to be able to understand a concept completely once explained, and work within the rules of the concept. This of course is arbitrary, but not a completely useless question.