eja: use peirce_decomposition() method to get the Peirce decomposition.

diff --git a/mjo/eja/eja_element.py b/mjo/eja/eja_element.py
index f44bee1c3f20d3040f0f77d8ff472b08c1bb5e9e..4d3b071923b2c275ecb559c8d60d183696c729ac 100644 (file)
--- a/mjo/eja/eja_element.py
+++ b/mjo/eja/eja_element.py
@@ -620,19 +620,10 @@ class FiniteDimensionalEuclideanJordanAlgebraElement(IndexedFreeModuleElement):
             True
 
         """
-        # TODO: when the Peirce decomposition is implemented for real,
-        # we can use that instead of finding this eigenspace manually.
-        #
-        # Trivial eigenspaces don't appear in the list, so we default to the
-        # trivial one and override it if there's a nontrivial space in the
-        # list.
         if not self.is_idempotent():
             return False
 
-        J1 = VectorSpace(self.parent().base_ring(), 0)
-        for (eigval, eigspace) in self.operator().matrix().left_eigenspaces():
-            if eigval == 1:
-                J1 = eigspace
+        (_,_,J1) = self.parent().peirce_decomposition(self)
         return (J1.dimension() == 1)