From: Michael Orlitzky <michael@orlitzky.com>
Date: Wed, 2 Feb 2022 05:11:38 +0000 (-0500)
Subject: eja: fix parent of empty sum in element inverse().
X-Git-Url: https://gitweb.michael.orlitzky.com/?p=sage.d.git;a=commitdiff_plain;h=1a8af0a2d9398932b8e4ac2b35a7fb4d7094654c

eja: fix parent of empty sum in element inverse().
---

diff --git a/mjo/eja/eja_element.py b/mjo/eja/eja_element.py
index 6997766..85ec494 100644
--- a/mjo/eja/eja_element.py
+++ b/mjo/eja/eja_element.py
@@ -506,15 +506,18 @@ class FiniteDimensionalEJAElement(IndexedFreeModuleElement):
             True
         """
         not_invertible_msg = "element is not invertible"
-        if self.parent()._charpoly_coefficients.is_in_cache():
+
+        algebra = self.parent()
+        if algebra._charpoly_coefficients.is_in_cache():
             # We can invert using our charpoly if it will be fast to
             # compute. If the coefficients are cached, our rank had
             # better be too!
             if self.det().is_zero():
                 raise ZeroDivisionError(not_invertible_msg)
-            r = self.parent().rank()
+            r = algebra.rank()
             a = self.characteristic_polynomial().coefficients(sparse=False)
-            return (-1)**(r+1)*sum(a[i+1]*self**i for i in range(r))/self.det()
+            return (-1)**(r+1)*algebra.sum(a[i+1]*self**i
+                                           for i in range(r))/self.det()
 
         try:
             inv = (~self.quadratic_representation())(self)