Comparative analysis of the four-fermion contact interactions at e^+e^- and e^-e^- colliders

We study electron-electron contact-interaction searches in the process e^+e^-\to e^+e^- at a future e^+e^- Linear Collider with both beams longitudinally polarized. We evaluate the model-independent constraints on the coupling constants, emphasizing the role of beam polarization, and make a comparison with the case of e^+e^-\to\mu^+\mu^-