Inflatonary model of a single scalar field with primordial potential
    V(\phi)=\frac{1}{2}m^2\phi^2+\frac{\lambda}{4}\phi^4 (m^2 >0) non-minimally
    coupled to gravity is studied in two-measures theory (TMT) in the Palatini
    formalism. In the equations of motion presented in the Einstein frame and
    rewritten in terms of the canonically normalized scalar field \varphi, there
    arises a TMT effective potential, which differs from the potential of the
    T-model in that it has a plateau of finite length: for \varphi greater a
    certain value varphi_0 the TMT effective potential becomes exponentially steep.
    The length of the plateau, and hence the duration of a quasi-de Sitter
    inflation, is controlled by a model parameter. The appearance of this
    parameter, as well as the form of the TMT effective potential, are a direct
    consequence of the features inherent only in TMT. A detailed analysis shows
    that there is a rather narrow interval of initial values of \varphi, bounded
    from above by \varphi_0, in which the initial kinetic \rho_{kin,in} and
    gradient \rho_{grad,in} energy densities turn out to be less than the potential
    energy density; this requires the only additional condition, which is that
    \rho_{kin,in}>\rho_{grad,in}. Therefore, in the space-time domain where these
    restrictions are satisfied, the initial conditions necessary for inflation are

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