:: HIDDEN semantic presentation

definition
mode set -> set ;
end;

definition
let c1, c2 be set ;
pred c1 = c2;
reflexivity
errorfrm
;
symmetry
errorfrm
;
end;

notation
let c1, c2 be set ;
antonym c1 <> c2 for c1 = c2;
end;

definition
let c1, c2 be set ;
pred c1 in c2;
asymmetry
errorfrm
;
end;