Fixes is_commutative for 1-dim matrix algebras (#1336)

thofma · Dec 23, 2023 · cf581d0 · cf581d0
1 parent 6aeaa90
commit cf581d0
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/src/AlgAss/AlgMat.jl b/src/AlgAss/AlgMat.jl
@@ -57,6 +57,14 @@ function is_commutative(A::AlgMat)
     return A.is_commutative == 1
   end
   dcr = dim_of_coefficient_ring(A)
+  if degree(A) == 1
+    if is_commutative(base_ring(A))
+      A.is_commutative = 1
+      return true
+    end
+    A.is_commutative = 2
+    return false
+  end
   if dim(A) == degree(A)^2*dcr
     A.is_commutative = 2
     return false