Silvio Bulgaretti

A Sharp Condition-Number Bound for a Tetrahedral Observation Operator

This paper proves a sharp global condition-number bound for a finite-dimensional tetrahedral observation operator. For every ordered triple of unit directions (n_1,n_2,n_3), the associated two-block Gramian satisfies \kappa_2(G)\ge 30. The bound is sharp, and equality is complete...

A Sharp Condition-Number Bound for a Tetrahedral Observation Operator

This paper proves a sharp global condition-number bound for a finite-dimensional tetrahedral observation operator. For every ordered triple of unit directions (n_1,n_2,n_3), the associated two-block Gramian satisfies \kappa_2(G)\ge 30. The bound is sharp, and equality is complete...

A Topology-Aware Mixed Finite-Element Formulation for Flux-Free Beltrami Modes in an Annular-Cylinder Domain

Version 1.1 adds the boundary-trace justification and direct source-level verification of the discrete boundary construction. This technical note reports a reproducible five-mesh numerical study of flux-free signed Beltrami modes on an annular-cylinder domain with solid-torus top...