the problem of lti is difficult because many bsees forget what it is after leaving class so we have to be very grammatically careful to write clearly for even a technical audience memristors are linear when solving a circuit at one point in time which is an important bit of linearity essentially lti theory developed to describe what fourier laplace transforms and lcr circuits and can do so it's surprising to an ee that a fundamental passive element would not work in that theory but it's not important to a non ee so we have to phrase it such that a non ee will gloss over and an ee stops and says what does that mean again because as you can see on this talk page a lot of people are getting confused on this particular point