Nontrivial summable extension under cotype
Determine whether a B-representation in a Banach space with non-trivial cotype can be chosen so that the associated summable ideal fSum((||x_n||^q)_n) is non-trivial.
References
However, it remains an open question whether one can choose the B-representation such that this summable ideal is non-trivial.
— $F_σ$-ideals, colorings, and representation in Banach spaces
(2501.15643 - Lopez-Abad et al., 26 Jan 2025) in Section 1, page 3; reiterated as Question 3.9, Section 3.1, page 12