deletions | additions       diff --git a/section_Challenegs_in_Bushy_Trees__.tex b/section_Challenegs_in_Bushy_Trees__.tex  index 64db5da..8b093c0 100644  --- a/section_Challenegs_in_Bushy_Trees__.tex  +++ b/section_Challenegs_in_Bushy_Trees__.tex 
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$$S(N) = \begin{cases}   1 & \text{if $N = 1$}; \\  $$\displaystyle $\displaystyle  \sum_{i=1}^{N} \frac{1}{n}$$ \frac{1}{n}$  & \text{if $N \ne 0$};.\end{cases} $$ 0$};.\end{cases}$$  Therefore the number of possible permutations are $S(N)*N!$. Unlike left-deep tree case, estimating the cost for all the possible bushy trees is computationally infeasible for moderately large N. Therefore it is required to come with a heuristic to select set of permutations for cost computations.Some heuristics considered are