A weak-localization effect has been studied in macroscopically inhomogeneous
2D system. It is shown, that although the real phase breaking length tends to
infinity when the temperature tends to zero, such a system can reveal a
saturated behavior of the temperature dependence of that parameter, which is
obtained from the standard analysis of the negative magnetoresistance and
usually identified by experimentalists with the phase braking length.Comment: 5 pages, 4 figure
