author paulson Thu, 12 Sep 1996 10:36:06 +0200 changeset 1983 f3f7bf0079fa parent 1982 38aafcab6890 child 1984 5cf82dc3ce67
Simplification and tidying of definitions
 src/HOL/Relation.thy file | annotate | diff | comparison | revisions
```--- a/src/HOL/Relation.thy	Thu Sep 12 10:35:11 1996 +0200
+++ b/src/HOL/Relation.thy	Thu Sep 12 10:36:06 1996 +0200
@@ -1,9 +1,7 @@
(*  Title:      Relation.thy
ID:         \$Id\$
-    Author:     Riccardo Mattolini, Dip. Sistemi e Informatica
-        and     Lawrence C Paulson, Cambridge University Computer Laboratory
-    Copyright   1994 Universita' di Firenze
-    Copyright   1993  University of Cambridge
+    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
+    Copyright   1996  University of Cambridge
*)

Relation = Prod +
@@ -16,11 +14,11 @@
Domain      :: "('a*'b) set => 'a set"
Range       :: "('a*'b) set => 'b set"
defs
-    id_def      "id == {p. ? x. p = (x,x)}"
-    comp_def    "r O s == {(x,z). ? y. (x,y):s & (y,z):r}"
+    id_def        "id == {p. ? x. p = (x,x)}"
+    comp_def      "r O s == {(x,z). ? y. (x,y):s & (y,z):r}"
trans_def     "trans(r) == (!x y z. (x,y):r --> (y,z):r --> (x,z):r)"
converse_def  "converse(r) == {(y,x). (x,y):r}"
Domain_def    "Domain(r) == {x. ? y. (x,y):r}"
Range_def     "Range(r) == Domain(converse(r))"
-    Image_def     "r ^^ s == {y. y:Range(r) &  (? x:s. (x,y):r)}"
+    Image_def     "r ^^ s == {y. ? x:s. (x,y):r}"
end```