Entry |
Value |
Name |
SURJECTIVE_EXISTS_THM |
Conclusion |
!f. (!y. ?x. f x = y) <=> (!p. (?x. p (f x)) <=> (?y. p y)) |
Constructive Proof |
No |
Axiom |
!t. t \/ ~t |
Classical Lemmas |
!t. ~ ~t <=> t!t. (t <=> T) \/ (t <=> F)!p. (?x. ~p x) <=> ~(!x. p x)!p. ~(!x. p x) <=> (?x. ~p x)!p. ~(?x. p x) <=> (!x. ~p x) |
Constructive Lemmas |
T!x. x = x!t. (!x. t) <=> t!t. ~ ~t <=> t!t. (F <=> t) <=> ~t!t. (T <=> t) <=> t!t. (t <=> F) <=> ~t!t. (t <=> T) <=> t!t. F ==> t <=> T!t. T ==> t <=> t!t. t ==> F <=> ~t!t. t ==> T <=> T!t. F \/ t <=> t!t. T \/ t <=> T!t. t \/ F <=> t!t. t \/ T <=> T!t. t \/ t <=> t!t. t ==> t!t. (t <=> T) \/ (t <=> F)!f y. (\x. f x) y = f y!p. (?x. ~p x) <=> ~(!x. p x)!p. ~(!x. p x) <=> (?x. ~p x)!p. ~(?x. p x) <=> (!x. ~p x)F <=> (!p. p)T <=> (\p. p) = (\p. p)~F <=> T~T <=> F(~) = (\p. p ==> F)(/\) = (\p q. (\f. f p q) = (\f. f T T))(==>) = (\p q. p /\ q <=> p)(\/) = (\p q. !r. (p ==> r) ==> (q ==> r) ==> r)(!) = (\p. p = (\x. T))(?) = (\p. !q. (!x. p x ==> q) ==> q) |
Contained Package |
function-thm |
Comment |
Standard HOL library retrieved from OpenTheory |