User talk:Duffifi

Hello world!

TakuyaMurata, regarding the edit at Normal operator, I did not understand the claim that $$\langle Sx, x \rangle = \langle Tx, x \rangle$$ implies $$S = T$$. It seems blatantly wrong in the case of real Hilbert spaces, for example, since there we have $$\langle Sx, x \rangle = \langle S^*x, x \rangle$$ for any operator $$S$$.


 * I have moved the discussion at my talkpage to that of Taku (talk) 01:33, 8 August 2009 (UTC)