If we have a Banach space $E$. and we consider it's dual $E^*$, it is a Banach space. so we consider the weak* topology ($\sigma(E^*,E)$) on $E^*$.
So My question is : If we have a set $B\subset E^*$, that is compact and Metrizable (weak* topology).
Why is $B$ is Metrizable complete ?
All compact metric spaces are sequentially compact. Thus, if you have a Cauchy sequence in a compact metric space, then this has a convergent subsequence. By the properties of a Cauchy sequence you can prove that the limit of this subsequence must also be the limit of the sequence. Therefore every compact metric space is complete.