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permute sum1 1. n : 2. f : n 3. L : (n-1) List
sum(f(compose_flips(L)(x)) | x < n) = sum(f(x) | x < n)
2. (n-1) List
3. u : (n-1)
4. v : (n-1) List
5. f:(n). sum(f(compose_flips(v)(x)) | x < n) = sum(f(x) | x < n)
f:(n). sum(f(compose_flips([u / v])(x)) | x < n) = sum(f(x) | x < n)
11 steps
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IF YOU CAN SEE THIS go to /sfa/Nuprl/Shared/Xindentation_hack_doc.html