*N* | size of the population |

*U* | mean number of new mutations per offspring |

*x*_{i} | the phenotype of individual *i* |

*H*_{i} | the haplotype of individual *i* |

| the phenotype of the most recent common ancestor (MRCA) |

| the additive genetic effect of a substitution at site *i* relative to the MRCA |

| the epistatic genetic effect of sites *i* and *j* relative to the MRCA |

| the variance in new random additive genetic effects that arise by mutation |

| the variance in new random epistatic genetic effects that arise by mutation |

| the expected variance of an additive genetic effect at site *i,* which is equal to if the effect is generated by a new mutation and equal to the variance in segregating additive effects if the mutation has been segregating for several generations |

*f* | the random and normally distributed variate by which the scaled additive genetic effects of mutations are multiplied to generate an epistatic genetic effect |

*ρ* | the average correlation between additive and epistatic genetics effects |

*r* | the intrinsic growth rate |

*α*(*x*_{i}, *x*_{j}) | a function that measures the amount of competition between individuals *i* and *j* with phenotypes *x*_{i} and *x*_{j} |

*a* | proportional to the rate of decline in frequency-dependent competition |

*n*_{α} | determines the way competition declines as phenotypes diverge between individuals. If *n*_{α} = 2, the decline has a Gaussian shape. As *n*_{α} becomes greater than two, the decline is weaker for small differences in phenotype, but stronger for large differences. As *n*_{α} becomes less than two, there is a more rapid decline in competition for small differences in phenotype, but more competition persists for large differences in phenotype |

*K*(*x*_{i}), κ(*x*_{i}) | functions that give the fitness of an individual with phenotype *x*_{i} owing to stabilizing selection, which is related to resource acquisition |

*K*_{0} | the intrinsic carrying capacity |

*x*_{opt} | the phenotype that optimally extracts resources |

*b* | proportional to the rate of decline in fitness owing to resource acquisition |

*n*_{K} | determines the way resource acquisition declines as a phenotype diverges from the optimal phenotype. Properties are similar to *n*_{α} |