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A sequence $(x_n)$ in a normed linear space $X$ is said to converge weakly to $x$ if $ \lim _{n\rightarrow\infty} \ell(x_n) = \ell(x)$ Consider the sequence $(f_n) \in C([0,1])$ defined by $f_n(t) = t^n.$ Does this sequence converge weakly? Does it have weakly convergent subsequences?

I don't really see the sequences here, do we get one different sequence depending on what $t$ is? $ \lim _{n\rightarrow\infty} \ell f_n(t) = 0, $ for $t \neq 1$. So it seems that f would converge to something not continuous?

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    You did not correctly state what weak convergence means. What is $\ell$?2012-11-27

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Consider evaluation functionals $ \mathrm{ev}_t:C([0,1])\to\mathbb{C}:f\mapsto f(t) $ Assume $(f_n)$ weakly converges to $f\in C([0,1])$, then $ f(t)=\lim\limits_{n\to\infty}\mathrm{ev}_t(f_n)=\lim\limits_{n\to\infty}f_n(t)= \begin{cases} 0\quad\mbox{ if }\quad t\neq 1\\ 1\quad\mbox{ if }\quad t= 1 \end{cases} $ Thus $f$ is discontinuous at $1$. Contradiction, so there is no weak limit for $(f_n)$. The same argument shows that $(f_n)$ have no weakly convergent subsequence.

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    @DamianSobota thank you!2013-04-23