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We present a general description of two mixed branes interactions. For this we consider two mixed branes with dimensions $p_1$ and $p_2$, in external field $B_{\mu\nu}$ and arbitrary gauge fields $A_{\alpha_1}^{(1)}$ and $A_{\alpha_2}^{(2)}$ on the world volume of them, in space-time in which some of its directions are compactified on circles with different radii. Some examples are considered to clear these general interactions. Finally contribution of the massless states on the interactions is extracted. Closed string with mixed boundary conditions and boundary state formalism, provide useful tools for calculation of these interactions.
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