Hello all, A.N. Krylov was a Russian naval engineer and applied mathematician. Although I'm not Russian myself, I decided to borrow his name for this forum, because I find him admirable. I'd like to extend my greetings to you all, hoping that I will now and then be able to contribute to answering questions while learning myself. My training is in mathematics, with an emphasis on applications of functional analysis to numerical analysis and dynamical systems, particularly those involving delayed feedback. After losing interest in the natural sciences for a while, I have recently found examples from classical physics and engineering very beautiful and motivating, particularly those stemming from mechanics. My best wishes, Krylov. P.S. My avatar is a picture of a "tippe top", one of my all-time favorite physical systems.