CPviolation in neutrinoless double beta decay and neutrino oscillation

Taking possible $\mathrm{CP}$ violations into account, we discuss constraints on lepton mixing angles obtained from neutrinoless double beta decay and from neutrino oscillation for three flavor Majorana neutrinos. From the CHORUS oscillation experiment, combined with the data from neutrinoless double beta decay, we show that the large angle solution for ${\theta }_{23}$ is improbable if the neutrino mass $m_3$ of the third generation is a candidate for hot dark matter.