on utilizing the spectral representation of selfadjoint operators in hilbert spaces, some error bounds in approximating $n$-time differentiable functions of selfadjoint operators in hilbert spaces via a taylor's type expansion are given.

For Maxwell operators in Lipschitz domains, we describe all m-dissipative boundary conditions and apply this result to generalized impedance Leontovich including the cases of singular, degenerate, randomized coefficients. To end construct Riesz bases trace spaces associated with curl-operator introduce a modified version triple adapted specifics equations, namely, mixed-order duality related sp...