In this paper, the notion of Fredholm tetrad of closed linear subspaces in a Banach space is introduced. Then the stability of the Fredholm tetrad is proved. After that, the notion of semi-compact perturbation of a closed linear subspace is introduced. Then for a of pair of closed linear subspace of a Banach space such that one is a semi-compact perturbation of the other, it is proved that the relative dimension between them is well-defined. If the perturbation is compact, the relative dimension is stable. Finally the perturbed argumented Morse index is studied.
No takes yet. Share an insight, caveat, or question.
Liao et al. (2024) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: