## Generalized Detailed Balance and Biological Applications

A detailed balance relation is an identity based on time reversal symmetry of time evolution equations. This identity, which is part of statistical mechanics, relates the probability of an evolution J->K and the reverse evolution K->J. Ambitious applications of detailed balance to biological replication have been proposed by J.R. England. Instead of using a stochastic dynamics approximation we look here at the deterministic time evolution, and obtain a detailed balance relation somewhat more general and than that used by England. This does however not seriously affect England’s biological discussion.