I see. Yeah, I mean more like the type of work where -- if you go back and read the initial papers -- the motivation was primarily engineering-related is long s

I see. Yeah, I mean more like the type of work where -- if you go back and read the initial papers -- the motivation was primarily engineering-related is long sense deprecated. And there is no reasonable new motivation. But lines of faculty have been working on it for long enough that everyone forgot why they still care about these "open problems".