Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2013/iii/paper-7/1/ii/solution

True. The Banach-Alaoglu theorem makes compact for the weak-star topology. Its compactness can be seen by embedding it in the product : the closed conditions expressing linearity identify a closed subset with , and the product is compact by the Tychonoff theorem. The product topology is exactly pointwise convergence on .
Part (i) supplies a compatible metric. Every compact metric space has a finite -net for each positive integer . The countable union of these finite nets is dense. Therefore
The argument concerns topological separability, with the relative weak-star topology specified in the question.

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