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Orbits/Writing/CurrentWriting/includes/Appendix_Survival_geometric...

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As we are analyzing survival rates, a geometric mean is better used to describe average effects.
By weighting the geometric mean with constellation sizes, we get:
\begin{align}
R_G = \exp \left[ \frac{1}{S_t} \sum^N_{j=1} s_t^j \ln(1-l^j(s^j_t,S_t,D_t)) \right]
\end{align}
The marginal effect is assumed to be negative, thus-
\begin{align}
0 > \parder{R_G}{s^i_t}{} =& \exp \left[ \frac{1}{S_t} \sum^N_{j=1} s_t^j \ln(1-l^j(s^j_t,S_t,D_t)) \right]
\left[ \parder{}{s^i_t}{} \frac{1}{S_t} \sum^N_{j=1} s_t^j \ln(1-l^j(s^j_t,S_t,D_t)) \right] \\
0 > \parder{R_G}{s^i_t}{} =& \frac{R_G}{S_t^2} \left[ S^t-
\left( \ln(1-l^i)-
- \frac{s^i_t}{1-l^i} \parder{l^i}{s^i_t}{}
- \sum^N_{j=1} \frac{s^j_t}{1-l^j} \parder{l^j}{S_t}{}
\right)-
- \sum^N_{j=1} s_t^j \ln(1-l^j) \right] \\
0 > \parder{R_G}{s^i_t}{} =& \frac{R_G}{S_t^2} \left[ S^t-
\left( \ln(R_i)-
- \frac{s^i_t}{1-l^i} \parder{l^i}{s^i_t}{}
- \sum^N_{j=1} \frac{s^j_t}{1-l^j} \parder{l^j}{S_t}{}
\right)-
- \sum^N_{j=1} s_t^j \ln(R_j) \right] \\
0 > & \ln R_i - \frac{s^i_t}{1-l^i} \parder{l^i}{s^i_t}{}
- \sum^N_{j=1} \frac{s^j_t}{1-l^j} \parder{l^j}{S_t}{} - \sum^N_{j=1} \frac{s_t^j}{S_t} \ln(R_j) \\
0 > & \ln R_i - \frac{s^i_t}{1-l^i} \parder{l^i}{s^i_t}{}
- \sum^N_{j=1} \frac{s^j_t}{1-l^j} \parder{l^j}{S_t}{} - \ln R_G \\
\ln \frac{R_G}{R_i} =& \ln R_G - \ln R_i > - \frac{s^i_t}{1-l^i} \parder{l^i}{s^i_t}{}
- \sum^N_{j=1} \frac{s^j_t}{1-l^j} \parder{l^j}{S_t}{}--
\end{align}