Multitype Galton-Watson Process

The population model is a multitype Galton-Watson process whose types are non-senescent biological ages. The mean offspring matrix counts both the mother-cell next state and the daughter-cell state. Cells in the Galton-Watson population evolve independently according to the single-cell transition rule. The expected offspring structure is symmetric in retention probability around p = 0.5. Each individual can produce at most two offspring, so the Galton-Watson growth-rate upper bound is below 2.