mjo/cone/isomorphism.py: cite Gowda/Trott for the l1-cone

diff --git a/mjo/cone/isomorphism.py b/mjo/cone/isomorphism.py
index 61cea422f693f59ee873682b5a25fbadf639ee4e..ff9785d50a0159d34c7376e6002a5933ff4442a1 100644 (file)
--- a/mjo/cone/isomorphism.py
+++ b/mjo/cone/isomorphism.py
@@ -65,6 +65,13 @@ def linear_isomorphisms(K1, K2):
     to vector-space isomorphisms of the lineality spaces and othogonal
     complements.
 
+    REFERENCES:
+
+    .. [GowdaTrott2014] \M. Seetharama Gowda and D. Trott. On the
+       irreducibility, Lyapunov rank, and automorphisms of special
+       Bishop–Phelps cones. Journal of Mathematical Analysis and
+       Applications, 419(1):172-184, 2014.
+
     SETUP::
 
         sage: from mjo.cone.isomorphism import linear_isomorphisms
@@ -107,7 +114,9 @@ def linear_isomorphisms(K1, K2):
 
     Automorphisms can be obtained by passing ``K2 == K1``. In this
     case, there are many duplicates so we use ``set()`` to obtain
-    only the unique automorphisms::
+    distinct transformations. Gowda and Trott_[GowdaTrott2014] have
+    computed the automorphism group of this cone, and we recover them
+    all up to a positive scalar::
 
         sage: K1 = Cone([(1,0,1), (-1,0,1), (0,1,1), (0,-1,1)])
         sage: set(linear_isomorphisms(K1,K1))
@@ -169,7 +178,6 @@ def linear_isomorphisms(K1, K2):
         ....:   for g in linear_isomorphisms(K1,K2)
         ....: )
         True
-
     """
     # There are no invertible maps between lattices of different
     # dimensions.