Statistical convergence, perturbation theory

Appendix 6. Brillouin-Wigner Perturbation Theory of the Quasi-species. Appendix 7. Renormalization of the Perturbation Theory Appendix 8. Statistical Convergence of Perturbation Theory Appendix 9. Variables, Mean Rate Constants, and Mean Selective Values for the Relaxed Error Threshold... 

In order to answer this question, a significant source of statistical correlation arising from mutation paths that visit a particularly advantageous mutant more than once must be considered. In the perturbation theory these paths are represented by products of factors involving the mutant replication rates, and it is necessary to remove the strong correlation that arises between these factors where repeated indices are present in order to obtain a tractable statistical analysis of convergence. The Watson renormalization procedure [29], the application of which to the steady-state quasi-species is summarized in Appendix 7, accomplishes just this [30]. The cost is a consecutive modification of the denominator, which may however be simplified to good approximation, as in Eqn. (A7.5). 

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