Nuprl - Proof: fun with inv is bij 1 1 1 1

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At: fun with inv is bij 1 1 1 1

1. A : Type
2. B : Type
3. f : A

B
4. g : B

A
5. g o f = Id
6. f o g = Id
7. a1 : A
8. a2 : A
9. f(a1) = f(a2)
10. g(f(a1)) = g(f(a2))

a1 = a2

By:	(NotThinning (With a1 (Analyze 5))) THEN (With a2 (Analyze 5))

Generated subgoal:

1 5. f o g = Id
6. a1 : A
7. a2 : A
8. f(a1) = f(a2)
9. g(f(a1)) = g(f(a2))
10. (g o f)(a1) = Id(a1)
11. (g o f)(a2) = Id(a2)
a1 = a2
2 steps

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