In this short note, we prove that the set of elementary tensors is weakly closed in the projective tensor product of two Banach spaces. As a result, we are able to answer a question from the literature proving that if $(x_n) \subset X$ and $(y_n) \subset Y$ are two weakly null sequences such that $(x_n \otimes y_n)$ converges weakly in $X \widehat{ \otimes}_\pi Y$, then $(x_n \otimes y_n)$ is also weakly null.

Categories: math.FA

The set of elementary tensors is weakly closed in projective tensor products