deletions | additions       diff --git a/A simple model.tex b/A simple model.tex  index 1109c77..22b5c4d 100644  --- a/A simple model.tex  +++ b/A simple model.tex 
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\end{align}   \begin{subequations}  \begin{align} \label{mylabel}  a_{t} & = \mu_{a} + \zeta_{a,t} + \sigma_{a} w_{a,t} , \quad w_{\zeta_a,t+1} \overset{iid}{\sim} N(0,1) \\  \zeta_{a,t} & = \rho_a \zeta_{a,t-1} + \sigma_{\zeta_a} w_{\zeta_a, t} , \quad w_{a,t} \overset{iid}{\sim} N(0,1) \end{align}  \end{subequations}  This is the same processes for productivity specified in \cite{Edge2007}, you can obtain their system of equations by defining \footnote{I've chosen this formulation because make comparisons to \cite{Edge2007} easy. An alternative formulation that is more natural in a state space formulation, and that allows easily to consider correlation between tfp}