Merge pull request sympy#12183 from parsoyaarihant/intersection

Empty intersection returns UniversalSet
mamakancha · Feb 18, 2017 · 62b1996 · 62b1996
2 parents 93eb73d + 99fb2e1
commit 62b1996
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diff --git a/sympy/sets/sets.py b/sympy/sets/sets.py
@@ -1469,7 +1469,7 @@ def flatten(arg):
         args = flatten(args)
 
         if len(args) == 0:
-            return S.EmptySet
+            return S.UniversalSet
 
         # args can't be ordered for Partition see issue #9608
         if 'Partition' not in [type(a).__name__ for a in args]:

diff --git a/sympy/sets/tests/test_sets.py b/sympy/sets/tests/test_sets.py
@@ -311,6 +311,8 @@ def test_intersection():
 
     assert Intersection(S.Complexes, FiniteSet(S.ComplexInfinity)) == S.EmptySet
 
+    # issue 12178
+    assert Intersection() == S.UniversalSet
 
 def test_issue_9623():
     n = Symbol('n')