Skip to main content
3 events
when toggle format what by license comment
Oct 3, 2015 at 21:34 comment added Dongyang Chen I forget the basic fact mainly because I have never taught functional analysis in my university. In fact, in my question, we can let $S=T^{*}J_{X}$, where $J_{X}:X\rightarrow X^{**}$ is the canonical embedding. Anyway, thanks, Bill.
Oct 3, 2015 at 18:47 comment added Bill Johnson Yes. If $T:Y\to X^*$ is even just weakly compact, then $T^{**}$ maps $Y^{**}$ into $X^*$ and extends $T$. In a first course in functional analysis one should learn that an bounded linear operator $S:V\to U$ is weakly compact if and only if $S^{**}V^{**} \subset U^{**}$. So this question is arguably more appropriate for another site. (I say ``arguably" because such a basic fact is probably hard to find in text books on real analysis.)
Oct 3, 2015 at 16:32 history asked Dongyang Chen CC BY-SA 3.0