If you look here http://planetmath.org/encyclopedia/RiezsLemma.html [Broken], there seems to be something missing - nothing is said about the norm of (x_alpha) or about the norm of (s - x_alpha).(adsbygoogle = window.adsbygoogle || []).push({});

Now, the same thing seems to happen here http://planetmath.org/encyclopedia/CompactnessOfClosedUnitBallInNormedSpaces.html [Broken], so I guess there's something about the notation that I'm not getting, rather than there being something actually missing.

Can anyone help? To be honest, I fail to see how "lx_alphal and ls-x_alphal for every s in S" could be a statement.

NB: The notation l.l is used to denote norm on the quoted webpages, rather than the more usual ll.ll

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# Homework Help: What does this notation mean?

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