From: Michael Orlitzky <michael@orlitzky.com>
Date: Thu, 27 Jan 2022 21:31:08 +0000 (-0500)
Subject: hurwitz.py: swap is_sker_hermitian() for is_skew_symmetric().
X-Git-Url: https://gitweb.michael.orlitzky.com/?a=commitdiff_plain;h=6c7b006daa3f6be00e49696b617fe9159cba85cd;p=sage.d.git

hurwitz.py: swap is_sker_hermitian() for is_skew_symmetric().

It turns out I've been working with the wrong concept for the past two
days. Welp.
---

diff --git a/mjo/hurwitz.py b/mjo/hurwitz.py
index c213283..6767fe1 100644
--- a/mjo/hurwitz.py
+++ b/mjo/hurwitz.py
@@ -385,8 +385,9 @@ class HurwitzMatrixAlgebraElement(MatrixAlgebraElement):
                     for j in range(self.ncols()) )
 
 
-    def is_skew_hermitian(self):
+    def is_skew_symmetric(self):
         r"""
+        Return whether or not this matrix is skew-symmetric.
 
         SETUP::
 
@@ -398,15 +399,23 @@ class HurwitzMatrixAlgebraElement(MatrixAlgebraElement):
             sage: A = ComplexMatrixAlgebra(2, QQbar, ZZ)
             sage: M = A([ [ 0,I],
             ....:         [-I,1] ])
-            sage: M.is_skew_hermitian()
+            sage: M.is_skew_symmetric()
             False
 
+        ::
+
+            sage: A = ComplexMatrixAlgebra(2, QQbar, ZZ)
+            sage: M = A([ [   0, 1+I],
+            ....:         [-1-I,   0] ])
+            sage: M.is_skew_symmetric()
+            True
+
         ::
 
             sage: A = HurwitzMatrixAlgebra(2, AA, QQ)
             sage: M = A([ [1, 1],
             ....:         [1, 1] ])
-            sage: M.is_skew_hermitian()
+            sage: M.is_skew_symmetric()
             False
 
         ::
@@ -414,13 +423,13 @@ class HurwitzMatrixAlgebraElement(MatrixAlgebraElement):
             sage: A = ComplexMatrixAlgebra(2, QQbar, ZZ)
             sage: M = A([ [2*I   ,  1 + I],
             ....:         [-1 + I, -2*I] ])
-            sage: M.is_skew_hermitian()
-            True
+            sage: M.is_skew_symmetric()
+            False
 
         """
-        # A tiny bit faster than checking equality with the conjugate
-        # transpose.
-        return all( self[i,j] == -self[j,i].conjugate()
+        # A tiny bit faster than checking equality with the negation
+        # of the transpose.
+        return all( self[i,j] == -self[j,i]
                     for i in range(self.nrows())
                     for j in range(self.ncols()) )