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Sep 26, 2019 at 17:52 comment added Jesse Peterson It might be worth pointing out that if $H$ is separable then the SOT-topology is metrizable when you restrict to norm bounded subsets.
Sep 25, 2019 at 7:44 history edited YCor CC BY-SA 4.0
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Sep 25, 2019 at 7:07 history edited javi1996 CC BY-SA 4.0
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Sep 24, 2019 at 14:30 history edited javi1996 CC BY-SA 4.0
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Sep 24, 2019 at 14:16 comment added javi1996 Yes, but I'm not including the hypothesis of being *-subalgebras, just only a subalgebra.
Sep 24, 2019 at 14:13 comment added Yemon Choi So just to try and pin down a precise question: you are asking if there is an infinite-dimensional $*$-subalgebra of ${\mathcal B}(\ell_2)$ in which every SOT-convergent sequence is automatically norm-convergent?
Sep 24, 2019 at 14:07 comment added javi1996 Yes, that what I mean. It is easy to see that it cannot happen in the whole algebra, but are there any infinite-dimensional subalgebras with this property?
Sep 24, 2019 at 13:46 comment added Yemon Choi What do you mean by asking for two topologies to "coincide sequentially"? Are you asking if every sequence that converges in SOT automatically converges in norm? Because if so, a simple counterexample is given by taking $P_n\in {\mathcal B}(\ell_2)$ to be the orthogonal projection onto the span of the $n$th standard basis vector; we have $P_n\to 0$ in SOT while $\Vert P_n\Vert=1$ for all $n$
Sep 24, 2019 at 13:33 history edited Ivan Izmestiev CC BY-SA 4.0
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Sep 24, 2019 at 13:30 review First posts
Sep 24, 2019 at 13:44
Sep 24, 2019 at 13:28 history asked javi1996 CC BY-SA 4.0