VectorFieldFreeModule: Update methods exterior_power, dual_exterior_power, tensor_module for changed FiniteRankFreeModule.__init__

Author: Matthias Koeppe

src/sage/manifolds/differentiable/vectorfield_module.py

@@ -1700,11 +1700,17 @@ def tensor_module(self, k, l):
             for more examples and documentation.
 
         """
-        from sage.manifolds.differentiable.tensorfield_module import \
+        try:
+            return self._tensor_modules[(k,l)]
+        except KeyError:
+            if (k, l) == (1, 0):
+                T = self
+            else:
+                from sage.manifolds.differentiable.tensorfield_module import \
                                                           TensorFieldFreeModule
-        if (k,l) not in self._tensor_modules:
-            self._tensor_modules[(k,l)] = TensorFieldFreeModule(self, (k,l))
-        return self._tensor_modules[(k,l)]
+                T = TensorFieldFreeModule(self, (k,l))
+            self._tensor_modules[(k,l)] = T
+            return T
 
     def exterior_power(self, p):
         r"""
@@ -1754,13 +1760,19 @@ def exterior_power(self, p):
             for more examples and documentation.
 
         """
-        from sage.manifolds.differentiable.multivector_module import \
+        try:
+            return self._exterior_powers[p]
+        except KeyError:
+            if p == 0:
+                L = self._ring
+            elif p == 1:
+                L = self
+            else:
+                from sage.manifolds.differentiable.multivector_module import \
                                                           MultivectorFreeModule
-        if p == 0:
-            return self._ring
-        if p not in self._exterior_powers:
-            self._exterior_powers[p] = MultivectorFreeModule(self, p)
-        return self._exterior_powers[p]
+                L = MultivectorFreeModule(self, p)
+            self._exterior_powers[p] = L
+            return L
 
     def dual_exterior_power(self, p):
         r"""
@@ -1808,13 +1820,17 @@ def dual_exterior_power(self, p):
             for more examples and documentation.
 
         """
-        from sage.manifolds.differentiable.diff_form_module import \
+        try:
+            return self._dual_exterior_powers[p]
+        except KeyError:
+            if p == 0:
+                L = self._ring
+            else:
+                from sage.manifolds.differentiable.diff_form_module import \
                                                       DiffFormFreeModule
-        if p == 0:
-            return self._ring
-        if p not in self._dual_exterior_powers:
-            self._dual_exterior_powers[p] = DiffFormFreeModule(self, p)
-        return self._dual_exterior_powers[p]
+                L = DiffFormFreeModule(self, p)
+            self._dual_exterior_powers[p] = L
+            return L
 
     def general_linear_group(self):
         r"""