| | Who Cites hhd? |
|
| hhd | Def hd ==  l:'a List. if null(l) then arb('a) else head(l) fi |
| | | Thm*  'a:S. hd  (hlist('a)   'a) |
|
| head | Def head(l) == hd(l) |
| | | Thm* 'a:Type, l:'a List.  mt(l)   head(l) 'a |
|
| arb | Def arb(T) == InjCase(lem(T); x. x, "uu") |
| | | Thm* T:S. arb(T) T |
|
| null | Def null(as) == Case of as; nil  true ; a.as' false |
| | | Thm* T:Type, as:T List. null(as)  |
| | | Thm* null(nil) |
|
| bif | Def bif(b; bx.x(bx); by.y(by)) == if b x(*) else y(x.x) fi |
| | | Thm* A:Type, b:, x:(bA), y:((b)A). bif(b; bx.x(bx); by.y(by)) A |
|
| tlambda | Def (x:T. b(x))(x) == b(x) |
|
| hd | Def hd(l) == Case of l; nil "?" ; h.t h |
| | | Thm* A:Type, l:A List. ||l|| 1 hd(l) A |
