Fractional differential equations -- Positive fractional electrical circuits -- Descriptor linear electrical circuits and their properties -- Stability of positive standard linear electrical circuits -- Reachability, observability and reconstructability -- Standard and fractional linear circuits with feedbacks -- Minimum energy control of electrical circuits -- Fractional 2D systems described by the Roesser model -- Laplace transforms and Z-transforms -- Elementary operations on matrices -- Nilpotent matrices -- Drazin inverse matrix.