KIEV, Ukraine — The Ukrainian government launched talks Wednesday on decentralizing power as part of a European-backed peace plan but did not invite its main foes, the pro-Russia insurgents who have declared independence in the east. That deliberate oversight left it unclear what the negotiations might accomplish. In his opening remarks, acting President Oleksandr Turchynov said authorities were "ready for a dialogue" but insisted they will not talk to the separatists who have seized buildings and fought government troops across eastern Ukraine.