11 lines
248 B
Text
11 lines
248 B
Text
|
import standard
|
||
|
|
|
||
|
|
hypothesis I : Type
|
||
|
|
definition F (X : Type) : Type := (X → Prop) → Prop
|
||
|
|
hypothesis unfold : I → F I
|
||
|
|
hypothesis fold : F I → I
|
||
|
|
hypothesis iso1 : ∀x, fold (unfold x) = x
|
||
|
|
|
||
|
|
theorem iso2 : ∀x, fold (unfold x) = x
|
||
|
|
:= sorry
|