Exercises
[1DZ]Prerequisites:[1DM]. Find an example of function \(f:βββ\) with \(fβ C^β\) and such that, setting \(A=\{ x:f(x)=0\} \), the point \(0\) will be the only point of accumulation of \(A\), i.e. \(D(A)=\{ 0\} \). Compare this example with Prop. 6.8.4 in the notes [ 3 ] ; and with the example [1NQ].
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