Consider a discrete group G and a bounded self-adjoint convolution operator T on l2 (G); let σ (T) be the spectrum of T. The spectral theorem gives a unitary isomorphism U between l2 (G) and a direct ...

Inverse spectral problems for integro-differential operators address the challenge of reconstructing the underlying operator – often comprising both differential and integral components – from its ...

Analytic functions, defined by the property of being locally expressible as convergent power series, form a cornerstone of complex analysis. Differential operators, which act on these functions by ...