Nuprl - Pf decidable list exists 1 2 1 1 1 2

1. T: Type
2. P: TProp
3. L: T List
4. u: T
5. v: T List
6. Dec(xv.P(x))
7. P(u)

P(u) xv.P(x) (P(u) xv.P(x))

By: Unfold `decidable` 6 THEN Analyze 6

Generated subgoals:

1 6. xv.P(x)
7. P(u)
P(u) xv.P(x) (P(u) xv.P(x))

2 6. xv.P(x)
7. P(u)
P(u) xv.P(x) (P(u) xv.P(x))

About:

1	6. `xv.P(x)` 7. `P(u)` `P(u) xv.P(x) (P(u) xv.P(x))`
2	6. `xv.P(x)` 7. `P(u)` `P(u) xv.P(x) (P(u) xv.P(x))`