Factorization of weakly compact operators through reflexive spaces with bases

If T:X→Y is weakly compact and Y is separable with the bounded approximation property, must T factor through a reflexive Banach space with a Schauder basis?

Why it matters and what counts as progress

Why it matters: A basis strengthens general reflexive factorization and the target weakens earlier shrinking-basis assumptions on the range.

What counts as progress: A factorization theorem throughout the stated range-space class, or a counterexample retaining bounded approximation; arbitrary separable ranges form a different problem.

How the problem developed

  1. 1974 · Factorization theorem [1]

    William J. Davis, Tadeusz Figiel, William B. Johnson and Aleksander Pełczyński Introduced the interpolation construction factoring every weakly compact operator through a reflexive space; their basis refinement used a shrinking basis in the target space.

  2. 2016 · Open question [2]

    Kevin Beanland Asked whether the DFJP interpolation factorization can be arranged through a reflexive space with a Schauder basis beyond the shrinking-basis case.

  3. 19 Jul 2026 · Basis factorization [3]

    Antonio and Pablo Acuaviva; model-generated proof ideas were verified and refined by the authors Proved that every weakly compact T:X→Y factors through a reflexive space with a Schauder basis when Y is separable with the bounded approximation property; in particular when Y has a basis.

AI contribution

Sources

  1. Davis, Figiel, Johnson and Pełczyński, Factorization of weakly compact operators and the approximation property
  2. Kevin Beanland, Davis, Figiel, Johnson and Pełczyński factorization through spaces with a basis
  3. Acuaviva–Acuaviva AI-guided Banach-space proofs
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