(p : (x : A) -> Id (B x) (f x) (g x)) : Id ((y : A) -> B y) f g =
<i> \(a : A) -> (p a) @ i
-{-
+{-
To see that the definition of funExt makes sense we can compute its
faces:
--------------------------------------------------------------------------
o Definitional equality for J? Problem pointed out by Dan Licata
- with regularity for composition in the universe. However the
- system seems to work without regularity (this is work in
- progress).
+ with regularity for composition in the universe. However, the
+ system might still work without regularity (this is what is being
+ implemented in the no_regular branch).
o Meta-theoretical properties of the system and correctness of the
model. Formalization?
- o Integration of ideas into other proof assistants (eg Agda)?
+ o Integration of ideas into other proof assistants (e.g. Agda)?
-}
addCom (a : nat) : (b : nat) -> Id nat (add a b) (add b a) = split
zero -> <i> addZero a @ -i
- suc b' -> <i> comp nat (suc (addCom a b' @ i)) [ (i = 0) -> <j> suc (add a b')
- , (i = 1) -> <j> addSuc b' a @ -j ]
+ suc b' -> <i> comp (<_> nat) (suc (addCom a b' @ i)) [ (i = 0) -> <j> suc (add a b')
+ , (i = 1) -> <j> addSuc b' a @ -j ]
+
-}