Def Dec(P) == P P

Thm* A:Prop. Dec(A) Prop

Def {i..j} == {k:| i k < j }

Thm* m,n:. {m..n} Type

Def Sym x,y:T. E(x;y) == a,b:T. E(a;b) E(b;a)

Thm* T:Type, E:(TTProp). Sym x,y:T. E(x,y) Prop

Def Trans x,y:T. E(x;y) == a,b,c:T. E(a;b) E(b;c) E(a;c)

Thm* T:Type, E:(TTProp). Trans x,y:T. E(x,y) Prop

Def AB == B < A

Thm* i,j:. ij Prop

Def A == A False

Thm* A:Prop. (A) Prop