Nuprl - Some Definitions

le	`Def AB == B < A` `Thm* i,j:. ij Prop`
le_int	`Def i z j == j < z i` `Thm* i,j:. i z j`
assert	`Def b == if b True else False fi` `Thm* b:. b Prop`
iff	`Def P Q == (P Q) & (P Q)` `Thm* (A B) Prop`
not	`Def A == A False` `Thm* (A) Prop`
lt_int	`Def i < z j == if i < j true ; false fi` `Thm* i,j:. i < z j`
bnot	`Def b == if b false else true fi` `Thm* b:. b`
ifthenelse	`Def if b t else f fi == dec(b ; t; f)` `Thm* b:, A:Type, p,q:A. if b p else q fi A`
rev_implies	`Def P Q == Q P` `Thm* (A B) Prop`
bfalse	`Def false ==` `Thm* false`
btrue	`Def true ==` `Thm* true`