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Fast Polynomial Multiplication using FFT

- Point Value Representation of Polynomial
- Linear time polynomial multiplication in point value form
- Collapsible Set ($n$ $n^{th}$ roots of unity)
- Computing a polynomial in $O(nlogn)$ time on a collapsible set of size $n$
- Converting from point value form to standard polynomial form in $O(nlogn)$ time using the fact that Inverse of the Vandermonde matrix is just a permutation of the rows of the Vandermonde matrix