3 papers
math.NA2025
A Two-Stage Finite Element Approach for High-precision Guaranteed Lower Eigenvalue Bounds
Xuefeng Liu, Michael Plum
Obtaining high-precision guaranteed lower eigenvalue bounds remains difficult, even though the standard high-order conforming finite element (FEM) easily yields extremely sharp upp…
math.SP2025
Stable Computation of Laplacian Eigenfunctions Corresponding to Clustered Eigenvalues
Ryoki Endo, Xuefeng Liu
The accurate computation of eigenfunctions corresponding to tightly clustered Laplacian eigenvalues remains an extremely difficult problem. In this paper, using the shape differenc…
math.SP2025
The second Dirichlet eigenvalue is simple on every non-equilateral triangle
Ryoki Endo, Xuefeng Liu
The Dirichlet eigenvalues of the Laplacian on a triangle that collapses into a line segment diverge to infinity. In this paper, to track the behavior of the eigenvalues during the…