Title: Green's function formalism for highly correlated systems
Author(s):

	F.Mancini (Dipartimento di Fisica ``E.R. Caianiello'' - Unità CNISM di Salerno Università degli Studi di Salerno, I-84081 Baronissi (SA), Italy) ,
	A.Avella (Dipartimento di Fisica ``E.R. Caianiello'' - Unità CNISM di Salerno Università degli Studi di Salerno, I-84081 Baronissi (SA), Italy)

We present the Composite Operator Method (COM) as a modern approach to the study of strongly correlated electronic systems, based on the equation of motion and Green's function method. COM uses propagators of composite operators as building blocks at the basis of approximate calculations and algebra constrains to fix the representation of Green's functions in order to maintain the algebraic and symmetry properties.

Key words: strongly correlated systems, Green's function formalism, equations of motion approach, composite operator method

PACS: 71.10.-w, 71.27.+a, 71.10.Fd