deletions | additions       diff --git a/Challenge Structure.tex b/Challenge Structure.tex  index fa2cc21..2783016 100644  --- a/Challenge Structure.tex  +++ b/Challenge Structure.tex 
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The overall goal of TDC0 and TDC1 is to carry out a blind test of current state of the art time-delay estimation algorithms in order to quantify the available accuracy. Criteria for success depend on the time-horizon. At present, time-delay cosmology is limited by the number of lenses with measured light curves and by the modeling uncertainties which are of order 5\% per system. Furthermore, distance measurements are currently in the range of accuracy of 3\%. Therefore, any method that can provide time-delays with realistic uncertainties ($\chi^2<1.5fN$) for the majority ($f>0.75$) of light curves with accuracy $A$ and precision $P$ better than 3\% can be considered a viable method.  In the longer run, with LSST in mind, a desirable goal is to achieve $A<0.002$ {\bf in order not to be systematics limited, while retaining the same average precision $P$ from whence the target 0.2/% 0.2\%  cosmographic precision comes from}. For $N=1000$, the 2-sigma goodness of fit requirement becomes $\chi^2 < 1.09 fN$, while keeping $f>0.5$. Testing for such extreme accuracy requires a large sample of lenses: TDC1 will contain several thousand simulated systems to enable such tests.