2 files changed, 27 insertions, 0 deletions
diff --git a/prolog/problems/family_relations/ancestor_2/common.py b/prolog/problems/family_relations/ancestor_2/common.py
new file mode 100644
index 0000000..61472b6
--- /dev/null
+++ b/prolog/problems/family_relations/ancestor_2/common.py
@@ -0,0 +1,13 @@
+id = 100
+group = 'family_relations'
+number = 7
+visible = True
+facts = 'family_relations'
+
+solution = '''\
+ancestor(X, Y) :-
+  parent(X, Y).
+ancestor(X, Y) :-
+  parent(X, Z),
+  ancestor(Z, Y).
+'''
diff --git a/prolog/problems/family_relations/ancestor_2/en.py b/prolog/problems/family_relations/ancestor_2/en.py
new file mode 100644
index 0000000..4853e15
--- /dev/null
+++ b/prolog/problems/family_relations/ancestor_2/en.py
@@ -0,0 +1,14 @@
+id = 100
+name = 'ancestor/2'
+slug = 'the ancestor relation'
+
+description = '''\
+<p><code>ancestor(X, Y)</code>: <code>X</code> is an ancestor (parent, grandparent,...) of <code>Y</code>.</p>
+<pre>
+  ?- ancestor(patricia, X).
+    X = john ;
+    X = michael ;
+    X = michelle.
+</pre>'''
+
+hint = {}