Rare decays of \eta-meson: the background of \rho- and \omega- mesons

The problem of $\rho$- and $\omega$- mesons contributions to the background for $\eta \to {\pi }^0{e}^{+}{e}^{-}$ decay and to the asymmetries in the decays $\eta \to \pi^+\pi^-\pi^0$and$\eta \to \pi^+\pi^-\gamma$ is considered.