  We present results of the study of the non-monotonous behavior of the
Lifshitz line as a function of temperature in ternary
homopolymer/diblock-copolymer mixtures. The non-monotonous behavior of the
Lifshitz line is due to the wave vector dependence of fluctuational
corrections, which we treat in the framework of the renormalization group
method. Our results are in agreement with the experimental findings of Schwahn
et al.[1,2]
