Spectral identities for band spectrum in one-dimensional case

Two models with band spectrum are considered: a one-dimensional lattice model based on the theory of extensions and a one-dimensional Schrödinger equation with periodic potential (Hill's equation). Relationships are obtained between the Bloch functions (Floquet solutions), the dispersion, and the effective masses at the edges of the spectral bands, on the one hand, the parameters of the models, on the other.