| | Some definitions of interest. |
|
| hhd | Def hd ==  l:'a List. if null(l) then arb('a) else head(l) fi |
| | | Thm*  'a:S. hd  (hlist('a)   'a) |
|
| arb | Def arb(T) == InjCase(lem(T); x. x, "uu") |
| | | Thm* T:S. arb(T) T |
|
| 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 |
|
| head | Def head(l) == hd(l) |
| | | Thm* 'a:Type, l:'a List. mt(l)   head(l) 'a |
|
| mt | Def mt(l) == Case of l; nil True ; a.as' False |
| | | Thm* 'a:Type{i}, l:'a List. mt(l) Prop{1} |
|
| not | Def A == A False |
| | | Thm* A:Prop. (A) Prop |
|
| null | Def null(as) == Case of as; nil true ; a.as' false |
| | | Thm* T:Type, as:T List. null(as) |
| | | Thm* null(nil) |
|
| stype | Def S == {T:Type|  x:T. True } |
| | | Thm* S Type{2} |
