A systematic approach to reduced GLT

This paper concerns the spectral analysis of matrix-sequences that are generated by discretization and numerical approximation partial differential equations (PDEs), in case domain is a generic Peano-Jordan measurable set. It observed such often present symbol, function describing asymptotic behaviour eigenvalues. When hypercube, can be conducted using theory generalized locally Toeplitz (GLT) sequences, but domain, new kind has to formalized. We thus introduce Reduced GLT sequences symbols, developing full detail its theory, presenting some application finite differences elements for convection-diffusion-reaction equations.