3 papers
math.FA2026
Grothendieck's theorem for Bessel sequences
Lukas Liehr, Mitchell A. Taylor, Peiyang Yu
We establish a sharp version of Grothendieck's theorem for Bessel sequences. Precisely, given a Bessel sequence with Bessel bound in a Hilbert spac…
math.FA2026
On the refined properties of uniformly quasi-greedy bases
Peiyang Yu
In this paper, we study some refined properties of uniformly quasi-greedy bases. In particular, we characterize the stability of uniformly quasi-greediness under scalings with boun…
math.NA2026
A Mixed Finite Element Method for the Dirichlet Vector Laplacian in Three Dimensions
Ralf Hiptmair, Peiyang Yu, Tianwei Yu
This work establishes the well-posedness and a priori error analysis for the mixed FEEC-type finite element approximation of the three-dimensional vector Laplace boundary value pro…