Nuprl - Pf append_segment 1 1 1 1 1

1. T: Type
2. as: T*
3. i: {0...||as||}
4. j: {i...||as||}
5. k: {j...||as||}
6. x:
7. x = j-i
8. j = x+i

(firstn(x;nth_tl(i;as)) @ firstn(k-(x+i);nth_tl(x+i;as))) = firstn(k-i;nth_tl(i;as))

By: Assert (kx+i)

Generated subgoal:

1 9. kx+i
(firstn(x;nth_tl(i;as)) @ firstn(k-(x+i);nth_tl(x+i;as))) = firstn(k-i;nth_tl(i;as))

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