From: Michael Orlitzky <michael@orlitzky.com>
Date: Wed, 3 Mar 2021 16:27:28 +0000 (-0500)
Subject: eja: fix the basis for the octonion matrix algebra.
X-Git-Url: https://gitweb.michael.orlitzky.com/?a=commitdiff_plain;h=3a5389fbc9ae5449e162958c0fda44de90d7e760;p=sage.d.git

eja: fix the basis for the octonion matrix algebra.
---

diff --git a/mjo/eja/eja_algebra.py b/mjo/eja/eja_algebra.py
index d7010bc..18138f4 100644
--- a/mjo/eja/eja_algebra.py
+++ b/mjo/eja/eja_algebra.py
@@ -2641,7 +2641,13 @@ class OctonionHermitianEJA(FiniteDimensionalEJA, MatrixEJA):
                 else:
                     for e in es:
                         E_ij  = MS.monomial( (i,j,e)             )
-                        E_ij += MS.monomial( (j,i,e.conjugate()) )
+                        ec = e.conjugate()
+                        # If the conjugate has a negative sign in front
+                        # of it, (j,i,ec) won't be a monomial!
+                        if (j,i,ec) in MS.indices():
+                            E_ij += MS.monomial( (j,i,ec) )
+                        else:
+                            E_ij -= MS.monomial( (j,i,-ec) )
                         basis.append(E_ij)
 
         return tuple( basis )