%% UMBC CMSC 331 01, Fall 2013 HW7
%% YOUR NAME, YOUREMAIl@umbc.edu


% base relations that should be specified as facts include: parent/2,
% spouse1/2, male/1 and female/1
%   parent(X,Y) iff X is a parent of Y
%    spouse1(X,Y) iff S is a spouse of Y
%    male(X) iff X is male
%    female(X) iff X is female


child(X,Y) :- 
  % true if X is a child of Y
  fail.

daughter(X,Y) :-
  % true if X is a daughter of Y
  fail.

mother(X,Y) :- 
  % true if X is the mother of Y. 
  fail.

sibling(X,Y) :-
  % true if X and Y are siblings (i.e. have the same biological
  % parents). Be sure your definition does not lead to one being ones sibling
  fail.

brother(X,Y) :- 
  % true if X is a brother of Y, e.g., X is a male sibling of y
  fail.

sister(X,Y) :- 
  % true if X is a sister of Y, e.g., X is a female sibling of y
  fail.

grandparent(X,Y) :- 
  % true of X is a grandparent of Y, e.g., X is a parent of some Z who
  % is also a parent of Y
  fail.

grandmother(X,Y) :- 
  % true of X is a grandmother of Y, e.g., X is a female grandparent
  % of Y
  fail.

uncle(X,Y) :- 
  % true if X is an uncle of Y, i.e. the brother of a parent.
  fail.

uncle(X,Y) :- 
  % true if X is an uncle of Y, i.e. the male spouse of a sibling of a
  % parent
  fail.

sister_in_law(X,Y) :- 
  % X is the sister-in-law of Y if X is the female spouse of Y's sibling
  fail.

sister_in_law(X,Y) :- 
  % X is the sister-in-law of Y if X is the sister of Y's spouse
  fail.

sister_in_law(X,Y) :-
  % X is the sister-in-law of Y if X is the spouse of Y's brother
  fail.


mother_in_law(X,Y) :-
  % X is the mother_in_law of Y if if X is the mother of Y's sopuse
  fail.

wife(X,Y) :- 
  % X is the wife of Y if X is Y's female spouse
  fail.

ancestor(X,Y) :- 
  % X is an ancestor of Y if X is a parent of Y
  fail.

ancestor(X,Y) :- 
  % X is an ancestor of Y if P is a parent of Y and X is an acestor of P
  fail.

descendant(X,Y) :- 
  % X is a descendant of Y if Y is an ancestor of X
  fail.

relative_by_blood(X,Y) :- 
  % X is an relative_by_blood of Y if X and Y share an ancestor
  fail.