Semi-embeddings and weakly sequential completeness of the projective tensor product
We show that if is a boundedly complete, unconditional Schauder decomposition of a Banach space X, then X is weakly sequentially complete whenever is weakly sequentially complete for each k ∈ ℕ. Then through semi-embeddings, we give a new proof of Lewis’s result: if one of Banach spaces X and Y has an unconditional basis, then X ⊗̂ Y, the projective tensor product of X and Y, is weakly sequentially complete whenever both X and Y are weakly sequentially complete.