The spectral flow, the Fredholm index, and the spectral shift function

2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/141223We discuss the well known ``Fredholm index=spectral flow'' theorem and show that it can be interpreted as a limit case of an identity involving two spectral shift functions.Submitted to M.Sh.Birman's 80th birthday issue of Trans. AMSSpectral TheoryFunctional Analysis47A53; 47A55The spectral flow, the Fredholm index, and the spectral shift functiontext