% problem-set/topology/point.set/lemma14.clauses
% created : 08/08/88
% revised : 08/17/89

% description : 
% 
% lemma 14: For any set ya, interior(ya) is a subset of ya, which 
%	in turn is a subset of closure(ya).

% representation : 
%
% See axioms.decl for a full explanation.

% denial: 

-subset_s(interior(A,X,T),A) | -subset_s(A,closure(A,X,T)).