Nuprl - Proof: swap adjacent instance 2 2 1 2 2 2

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At: swap adjacent instance 2 2 1 2 2 2

1. A : Type
2. P : A

Prop
3. X : A List
4. Y : A List
5. a : A
6. b : A
7. P(a,b)
8. i :

9. i<||X @ [b; a / Y]||
10.

i<||X||
11.

i = ||X||
12.

i = ||X||+1

(X @ [b; a / Y])[i] = (X @ [a; b / Y])[((||X||, ||X||+1)(i))]

By:	Subst' ((\|\|X\|\|, \|\|X\|\|+1)(i) = i) 0 THEN Try (Unfold `flip` 0 THEN Reduce 0 THEN Repeat SplitOnConclITE)

Generated subgoal:

1 (X @ [b; a / Y])[i] = (X @ [a; b / Y])[i]
2 steps

About:

IF YOU CAN SEE THIS go to /sfa/Nuprl/Shared/Xindentation_hack_doc.html