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Distributed computer systems may be used in various ways to find good solutions to difficult combinatorial optimization problems. An interesting approach consists in executing concurrently different search methods that exchange information gathered in previously explored regions of the solution space. This cooperation mechanism strongly impacts how the solution space is explored. We introduce a formal representation of such cooperative procedures based on discrete-time dynamical systems. We describe how the search behavior of cooperative programs depends on systems of complex and correlated interactions. We derive the notion of systemic cooperation and illustrate through simulations the relevance of this notion to the understanding of the search behavior of cooperative procedures.