From 326602c596658236784ad8cf325c382ed8b419c6 Mon Sep 17 00:00:00 2001
From: Jonathan Kliem <jonathan.kliem@fu-berlin.de>
Date: Tue, 15 Oct 2019 13:10:45 +0200
Subject: [PATCH] f_vector of CombinatorialPolyhedron is a vector

---
 .../polyhedron/combinatorial_polyhedron/base.pyx    | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/sage/geometry/polyhedron/combinatorial_polyhedron/base.pyx b/src/sage/geometry/polyhedron/combinatorial_polyhedron/base.pyx
index 741b5273525..bb75f73c42a 100644
--- a/src/sage/geometry/polyhedron/combinatorial_polyhedron/base.pyx
+++ b/src/sage/geometry/polyhedron/combinatorial_polyhedron/base.pyx
@@ -184,7 +184,7 @@ cdef class CombinatorialPolyhedron(SageObject):
     an integer::
 
         sage: CombinatorialPolyhedron(-1).f_vector()
-        (1,)
+        (1)
         sage: CombinatorialPolyhedron(0).f_vector()
         (1, 1)
         sage: CombinatorialPolyhedron(5).f_vector()
@@ -759,7 +759,7 @@ cdef class CombinatorialPolyhedron(SageObject):
 
             sage: C = CombinatorialPolyhedron(-1)
             sage: C.f_vector()
-            (1,)
+            (1)
             sage: C.n_facets()
             0
 
@@ -1117,12 +1117,19 @@ cdef class CombinatorialPolyhedron(SageObject):
             sage: C = CombinatorialPolyhedron(P)
             sage: C.f_vector()
             (1, 10, 45, 120, 185, 150, 50, 1)
+
+        TESTS::
+
+            sage: type(C.f_vector())
+            <type 'sage.modules.vector_integer_dense.Vector_integer_dense'>
         """
         if not self._f_vector:
             self._compute_f_vector()
         if not self._f_vector:
             raise ValueError("could not determine f_vector")
-        return self._f_vector
+        from sage.modules.free_module_element import vector
+        from sage.rings.all                   import ZZ
+        return vector(ZZ, self._f_vector)
 
     def face_iter(self, dimension=None, dual=None):
         r"""