From: Michael Orlitzky <michael@orlitzky.com>
Date: Tue, 16 Jul 2019 00:18:41 +0000 (-0400)
Subject: eja: add a test for power-operator-commutativity.
X-Git-Url: https://gitweb.michael.orlitzky.com/?a=commitdiff_plain;h=4156fccce1265f500fe432b0f5567e43fbbc23d6;p=sage.d.git

eja: add a test for power-operator-commutativity.
---

diff --git a/mjo/eja/euclidean_jordan_algebra.py b/mjo/eja/euclidean_jordan_algebra.py
index 3a98324..1426d5e 100644
--- a/mjo/eja/euclidean_jordan_algebra.py
+++ b/mjo/eja/euclidean_jordan_algebra.py
@@ -124,6 +124,18 @@ class FiniteDimensionalEuclideanJordanAlgebra(FiniteDimensionalAlgebra):
                 sage: (x*x)*(x*x*x) == x^5
                 True
 
+            We also know that powers operator-commute (Koecher, Chapter
+            III, Corollary 1)::
+
+                sage: set_random_seed()
+                sage: x = random_eja().random_element()
+                sage: m = ZZ.random_element(0,10)
+                sage: n = ZZ.random_element(0,10)
+                sage: Lxm = (x^m).matrix()
+                sage: Lxn = (x^n).matrix()
+                sage: Lxm*Lxn == Lxn*Lxm
+                True
+
             """
             A = self.parent()
             if n == 0: