Daniel Akech Thiong

$H$-Operator Approximation Spaces via Delayed Riesz Means and Quasi-Banach Moduli

We establish a constructive and quasi-Banach framework for approximation spaces $A_\mu^\rho$ of compact $H$-operators between Banach and quasi-Banach spaces. By leveraging delayed Riesz means $V_{2^{bn}}$ generated by self-adjoint differential operators $P(D)$, we replace abstract best approximants with explicit linear...