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@ -36,19 +36,45 @@ It is easily shown that this criteria is sufficient to guarantee Rao and Rondina
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It has three primary benefits:
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It has three primary benefits:
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\begin{itemize}
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\begin{itemize}
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\item % Can be solved for algebraically or numerically for a given, bounded state space.
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\item % Can be solved for algebraically or numerically for a given, bounded state space.
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The kessler region can be numerically described within bounded state spaces.
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The $\epsilon$-kessler region can be numerically described within bounded state spaces.
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\item % This is what you would actually compute.
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\item % This is what you would actually compute.
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In a Computational General Equilibrium Model, as most models of any complexity will be,
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In a computational model, as most models of any complexity will be,
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you cannot check for divergence numerically.
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you cannot check for divergence numerically.
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The condition given is a basic guarantee of the divergent behavior that is
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The condition given is a basic guarantee of the divergent behavior that is
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required for Kessler Syndrome and acknowledges computational limitations.
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required for Kessler Syndrome and acknowledges computational limitations.
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\item Finally, a slow divergence is no divergence in the grand scheme of things.
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\item Finally, a slow divergence is no divergence in the grand scheme of things.
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It is possible to have a mathematically divergent function, but one that is so slow,
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It is possible to have a mathematically divergent function, but one that is so slow,
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there is no noticable degree of debris growth before Sol enters a red giant phase.
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there is no noticable degree of debris growth before Sol enters a red giant phase.
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In this specification, it is possible to choose $\epsilon$ such that the divergent behavior
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In this specification, it is possible to choose $\epsilon$ such that the divergent behaviors
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has an impact on a meaningful timescale.
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identified have an impact on a meaningful timescale.
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% \item % Stochastic versions could might be describable as martigales.
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\end{itemize}
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\end{itemize}
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% Issue with this approach: What about cyclical behaviors?
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% Autocatalysis leads to high debris leads to reduced launches
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% which leads to debris decay leads to increased launches leads to Autocatalysis
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There is at least one issue with this definition of $\epsilon$-kessler regions.
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Let's define a ``proto-kesslerian'' region as the stock and debris levels such that:
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\begin{align}
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\kappa = \left\{ \{s^j_t\}, D_t :
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D_{t+1} - D_{t} \geq \epsilon > 0 \right\}
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\end{align}
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It may be, under certain situations, the case that optimal launch rates cycle along with
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debris and stock levels, leading to a cycle in and out of the proto-kesslerian regions.
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This is an issue because, assumning a stable cycle, Rao's definition
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of the kessler region would capture this behavior, but the $\epsilon$-kessler definition
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would not.
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I believe, but have not verified, that some choices of $\epsilon$, although permitting cycles,
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would relegate them to levels with minimal economic impact.
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%Maybe can be studies by phase or flow diagrams?
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%Area of research: What makes a good \epsilon?
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This leads to the important question of ``What makes a good value of $\epsilon$?''
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One method, in the spirit of \cite{Adilov2018}, is to choose a change in debris, $D_{t+1} - D_t$, such that
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the loss of satellites in periods $t+1$ to $t+k$ is increased by or to a certain percentage, say 50\%.
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I've put very little thought into addressing this general question so far,
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and need to analyze the implications of different choice rules.
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\end{document}
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\end{document}
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