let
E
be
set
;
:: thesis:
for
A
being
Subset
of
(
E
^omega
)
holds
A
+
=
(
A
*
)
^^
A
let
A
be
Subset
of
(
E
^omega
)
;
:: thesis:
A
+
=
(
A
*
)
^^
A
(
A
*
)
^^
A
=
A
|^..
1
by
Th30
;
hence
A
+
=
(
A
*
)
^^
A
by
Th50
;
:: thesis:
verum