Just Selection
- $\bar{f}(t) =$ average fitness of population at time $t$.
- $m(s,t) =$ instances of schema $s$ in population at time $t$.
- $\hat{u}(s,t) =$ average fitness of instances of $s$ at time $t$.
- Probability of selecting $h$ in one selection step is
\[
\array{
Pr(h) & = & \frac{f(h)}{\sum_{i=1}^{n} f(h_i)} \\
& = & \frac{f(h)}{n \bar{f}(t)}
}
\]
- Probabilty of selecting an instance of $s$ in one step
\[
\array{
\Pr(h \in s) & = & \sum_{h\in s \cap p_{t}} \frac{f(h)}{n \bar{f}(t)} \\
& = & \frac{\hat{u}(s,t)}{n \bar{f}(t)}m(s,t)
}
\]
- Expected number of instances of $s$ after $n$ selections
\[
\array{
E[m(s,t+1)] & = & \frac{\hat{u}(s,t)}{\bar{f}(t)}m(s,t)
}
\]
José M. Vidal
.
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