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At:
permute sum122121 1. n : 2. (n-1) List
3. u : (n-1)
4. v : (n-1) List
5. f:(n). sum((f o compose_flips(v))(x) | x < n) = sum(f(x) | x < n)
6. f : n 7. sum((f o (u, u+1) o compose_flips(v))(x) | x < n)
7. =
7. sum((f o (u, u+1))(x) | x < n)
sum((f o (u, u+1) o compose_flips(v))(x) | x < n)
=
sum(f(compose_flips([u / v])(x)) | x < n)
By:
BackThru
Thm*n:, f,g:(n).
Thm* (i:n. f(i) = g(i)) sum(f(x) | x < n) = sum(g(x) | x < n)
THEN
Using [`B',n] Auto
THEN
Unfold `compose_flips` 0
THEN
Unfold `compose_list` 0
THEN
Reduce 0
THEN
Fold `compose_list` 0
THEN
Fold `compose_flips` 0
THEN
Fold `member` 0