perfected :- name(ucc), possession,             not neg perfected.
neg perfected :- name(sma), ship, neg finstatement, not     perfected.

(Y < X) :- 
	name(lex_posterior(X,Y)),
	newer(X,Y),
	not neg (Y < X).
(X < Y) :- 
	name(lex_superior(X,Y)),
	state_law(X),
	federal_law(Y),
	not neg (X < Y).

possession.
ship.
neg finstatement.

newer(ucc,sma).
federal_law(sma).
state_law(ucc).

% (lex_posterior(X,Y) < lex_superior(X,Y)).