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  "body": "\n## Summary\n\nIn applied mathematics, a **bit-reversal permutation** is a [[permutation|05RWFKVTJ7]] of a [[sequence|0G9EKM0E15]] of $n$ items, where $n=2^k$ is a power of two. It is defined by indexing the elements of the sequence by the numbers from $0$ to $n-1$, representing each of these numbers by its binary representation (padded to have length exactly $k$), and mapping each item to the item whose representation has the same bits in the reversed order.\n",
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