src/HOL/Set.ML
changeset 4229 551684f275b9
parent 4159 4aff9b7e5597
child 4231 a73f5a63f197
     1.1 --- a/src/HOL/Set.ML	Fri Nov 14 15:51:09 1997 +0100
     1.2 +++ b/src/HOL/Set.ML	Sat Nov 15 13:10:52 1997 +0100
     1.3 @@ -610,6 +610,16 @@
     1.4  qed "image_iff";
     1.5  
     1.6  
     1.7 +goal Set.thy "(! x : f `` A. P x) = (! a:A. P(f a))";
     1.8 +by (Blast_tac 1);
     1.9 +qed "ball_image";
    1.10 +
    1.11 +goal Set.thy "(? x : f `` A. P x) = (? a:A. P(f a))";
    1.12 +by (Blast_tac 1);
    1.13 +qed "bex_image";
    1.14 +
    1.15 +Addsimps [ball_image,bex_image];
    1.16 +
    1.17  (*** Range of a function -- just a translation for image! ***)
    1.18  
    1.19  goal thy "!!b. b=f(x) ==> b : range(f)";