program.txt

% The program is a DATALOG with (stratified) negation program
% The "input" predicates are: (i), class, ins, ms, mg, ic, pi.
% The "output" predicates are: ins and link.
% The "auxiliary" predicates are: desc, ms', mg', ic', pi', pins, plink, nins, nlink.

% mg is the inverse of ms, and vice versa
mg(X, Y) :- ms(Y, X).
ms(X, Y) :- mg(Y, X).

% transitivity of ms, mg
mg(X, Y) :- mg(X, Z), mg(Z, Y).
%ms(X, Y) :- ms(X, Z), ms(Z, Y).

% similarity symmetry
p4(X, Y) :- p4(Y, X).
p3(X, Y) :- p3(Y, X).
% p2(X, Y) :- p2(Y, X).
% p1(X, Y) :- p1(Y, X).
% p0(X, Y) :- p0(Y, X).

% incomparable/either symmetry
ic(X, Y) :- ic(Y, X).

% If there is a contradiction in the generality/specificity
% evaluations, we set it to incomparable. Note that new instance-of
% relations are only created between A and B if not ic(A, B).
% This, together with the following 4 rules, resolves contradicting
% evaluations, by dissallowing isa relations but making links possible.
ic(X, Y) :- ms(X, Y), mg(X, Y), p4(X, Y).
ic(X, Y) :- ms(X, Y), mg(X, Y), p3(X, Y).


% descendant from the isa-relations only between classes
desc(X, Y) :- isa(X, Y), class(X), class(Y).
desc(X, Z) :- desc(X, Y), desc(Y, Z), class(X), class(Y), class(Z).


% [POSSIBLE INS]
% Individual X is possibly an instance of class Y if they are highly related,
% X is more specific than Y, and they are not incomparable.
pins(X, Y) :- p4(X, Y), ms(X, Y), class(Y), not class(X), not ic(X, Y).
pins(X, Y) :- p3(X, Y), ms(X, Y), class(Y), not class(X), not ic(X, Y).

% [NOT INS I]
% Do not make X an instance of class Y if there is a class Z of which
% X is possibly an instance and which is a descendant of Y.
nins(X, Y) :- pins(X, Z), desc(Z, Y), class(Y), class(Z), not class(X).

% [NOT INS II]
% Do not make X an instance of class Y if there is evidence for a link
% from class Y to class Z, no strong evidence against a link from class Y to class Z,
% and X is a possible instance of class Z.
% Note that if there is a possible link from class Y to class Z then
% class Z is more specific and highly related to class Y but not
% a descendant of class Y.
%added "not nlink(Y, Z)" as test--remove if not stratified
nins(X, Y) :- pins(X, Z), plink(Y, Z), not nlink(Y, Z),  class(Y), class(Z), not class(X).


% [POSSIBLE LINK I] 
% A link is possible from class X to class Y if these two classes are highly related
% if class Y is more specific than class X, class Y is not a desendant of X, class X is
% not a descendant of Y, and the two classes are not incomparable.
plink(X, Y) :- p4(Y, X), ms(Y, X), not desc(Y, X), not desc(X, Y), not ic(Y, X), class(X), class(Y).
plink(X, Y) :- p3(Y, X), ms(Y, X), not desc(Y, X), not desc(X, Y), not ic(Y, X), class(X), class(Y).

% [POSSIBLE LINK II]
% A link is possible from class X to individual Y if they are highly related,
% incomparable, X is not a descendant of Y, and Y is not a descendant of X.
% added check desc AND ancestor
plink(X, Y) :- p4(X, Y), ic(X, Y), not desc(Y, X), not desc(X, Y), class(X).
plink(X, Y) :- p3(X, Y), ic(X, Y), not desc(Y, X), not desc(X, Y), class(X).

% [NOT LINK I(a)] 
% Do not link to an instance Y of class Z if there is a possible link to Z.
nlink(X, Y) :- plink(X, Z), ins(Y, Z), class(X), not class(Y), class(Z).

% [NOT LINK I(b)]
% Do not link from class X to an individual Y if it is an instance
% of a descendant Z of class X.
nlink(X, Y) :- desc(Z, X), ins(Y, Z), class(X), not class(Y), class(Z).

% [NOT LINK I(c)]
% Do not link from class X to instance Y if Y is an instance of X.
nlink(X, Y) :- ins(Y, X), class(X), not class(Y).

% [NOT LINK II(a)] 
% Do not link from class X to a descendant Y of class Z if there is a possible
% link from class X to Z.
nlink(X, Y) :- plink(X, Z), desc(Y, Z), class(X), class(Y), class(Z).

% [NOT LINK II(b)] 
% Do not link from class X to a sibling Y of that class.
nlink(X, Y) :- isa(X, Z), isa(Y, Z), class(X), class(Y), class(Z).

% [NOT LINK II(c)]
% Do not link from a class to one of its superclasses.
nlink(X, Y) :- desc(X, Y), class(X), class(Y).

% [NOT LINK II(d)]
% Do not link from a class to one of its subclasses.
nlink(X, Y) :- desc(Y, X), class(X), class(Y).


% [CREATE INS]
ins(X, Y) :- pins(X, Y), not nins(X, Y).

% [CREATE LINK]
link(X, Y) :- plink(X, Y), not nlink(X, Y).