Searching all the configurations C′ which produce a given configuration C is an extremely hard task. The current approximations are based on heavy hand-made calculus by considering the specific features of the given configuration. In this paper we present a general method for characterizing all the configurations C′ which produce a given configuration C in the framework of transition P systems ...

In trying to improve Weinstock's results on approximation by holomorphic functions on certain product domains, we are led to estimates in Sobolev spaces for the ∂-operator on polycylinders for (γ, q)-forms. This generalizes our results for the same operator on poly-cylinders previously obtained, and can be applied to a number of other problems such as the Corona problem. 1. Introduction. Had we...