Weak topology.

I'm learning dual vector space and weak topology which help to build new "compact" theory. I think you remember Riesz's lemma about noncompactness of unit ball. The unit ball in l2 is closed relatively weak topology. It is very interesting.

P.S. I found very interesting mathematical site

Sometimes, it seems I understand Quantum mechanics. I realized some exersises (1-dimentinal, without spin). I understand how quantum solution cross to classic solution, their differences. Finally I have realized what steady state really means and how I can imagine some quantum solutions of classic exersises.