Consider two-type linear-fractional branching processes in varying environments with asymptotically constant mean matrices. Let $\nu$ be the extinction time. Under certain conditions, we show that both $P(\nu=n)$ and $P(\nu>n)$ are asymptotically the same as some functions of the products of spectral radii of the mean matrices. We also give an example for which $P(\nu=n)$ decays with various speeds such as $\frac{ c}{ n(\log n)^2},$ $\frac{ c}{ n^\beta},\beta >1$ et al. which are very different from the ones of homogeneous multitype Galton-Watson processes.
Categories: math.PR