From: Michael Orlitzky <michael@orlitzky.com>
Date: Tue, 15 Oct 2019 12:27:44 +0000 (-0400)
Subject: eja: define the trace of an element in a trivial algebra.
X-Git-Url: https://gitweb.michael.orlitzky.com/?a=commitdiff_plain;h=73ba2d67c0850074e655b4da61aa021e6d9b6816;p=sage.d.git

eja: define the trace of an element in a trivial algebra.
---

diff --git a/mjo/eja/eja_element.py b/mjo/eja/eja_element.py
index 2eb2677..bd45b17 100644
--- a/mjo/eja/eja_element.py
+++ b/mjo/eja/eja_element.py
@@ -1248,6 +1248,12 @@ class FiniteDimensionalEuclideanJordanAlgebraElement(IndexedFreeModuleElement):
         """
         P = self.parent()
         r = P.rank()
+
+        if r == 0:
+            # Special case for the trivial algebra where
+            # the trace is an empty sum.
+            return P.base_ring().zero()
+
         p = P._charpoly_coeff(r-1)
         # The _charpoly_coeff function already adds the factor of
         # -1 to ensure that _charpoly_coeff(r-1) is really what