:: HIDDEN semantic presentation
definition
mode
set
->
set
;
end;
definition
let
x
be
set
,
y
be
set
;
pred
c
1
=
c
2
;
reflexivity
errorfrm
;
symmetry
errorfrm
;
end;
notation
let
x
be
set
,
y
be
set
;
antonym
c
1
<>
c
2
for
c
1
=
c
2
;
end;
definition
let
x
be
set
,
X
be
set
;
pred
c
1
in
c
2
;
asymmetry
errorfrm
;
end;