eja: improve tests for morphism addition.

diff --git a/mjo/eja/euclidean_jordan_algebra.py b/mjo/eja/euclidean_jordan_algebra.py
index b239dc7287326f95815708ca3b80fd2c64d99b1a..fa11aed040a152de2cfe8f9c398b77af39c33276 100644 (file)
--- a/mjo/eja/euclidean_jordan_algebra.py
+++ b/mjo/eja/euclidean_jordan_algebra.py
@@ -30,31 +30,42 @@ class FiniteDimensionalEuclideanJordanAlgebraMorphism(FiniteDimensionalAlgebraMo
 
       3. Allows us to add morphisms in the obvious way.
 
+      4. Allows us to invert morphisms.
+
     If this seems a bit heavyweight, it is. I would have been happy to
     use a the ring morphism that underlies the finite-dimensional
     algebra morphism, but they don't seem to be callable on elements of
-    our EJA, and you can't add them.
+    our EJA, and you can't add/invert them.
     """
 
     def __add__(self, other):
         """
         Add two EJA morphisms in the obvious way.
 
-        EXAMPLES:
+        EXAMPLES::
 
             sage: J = RealSymmetricEJA(3)
             sage: x = J.zero()
-            sage: y = J.zero()
+            sage: y = J.one()
             sage: x.operator() + y.operator()
             Morphism from Euclidean Jordan algebra of degree 6 over Rational
             Field to Euclidean Jordan algebra of degree 6 over Rational Field
             given by matrix
-            [0 0 0 0 0 0]
-            [0 0 0 0 0 0]
-            [0 0 0 0 0 0]
-            [0 0 0 0 0 0]
-            [0 0 0 0 0 0]
-            [0 0 0 0 0 0]
+            [1 0 0 0 0 0]
+            [0 1 0 0 0 0]
+            [0 0 1 0 0 0]
+            [0 0 0 1 0 0]
+            [0 0 0 0 1 0]
+            [0 0 0 0 0 1]
+
+        TESTS::
+
+            sage: set_random_seed()
+            sage: J = random_eja()
+            sage: x = J.random_element()
+            sage: y = J.random_element()
+            sage: (x.operator() + y.operator()) in J.Hom(J)
+            True
 
         """
         P = self.parent()