The radical of a zero dimensional assoc. algebra

is the algebra itself; up to now, GAP ran into an error. (I have seen code that had to work around this error.)
gap-system · Sep 11, 2017 · b9bc370 · b9bc370
1 parent 71eb99e
commit b9bc370
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diff --git a/lib/algebra.gi b/lib/algebra.gi
@@ -2736,6 +2736,11 @@ InstallMethod( RadicalOfAlgebra,
     fi;
 
     n:= Dimension( A );
+
+    if n = 0 then
+      return A;
+    fi;
+
     BA:= Basis( A );
     bv:= BasisVectors( BA );
     F:= LeftActingDomain( A );

diff --git a/tst/testinstall/algmat.tst b/tst/testinstall/algmat.tst
@@ -133,6 +133,8 @@ gap> radc:= RadicalOfAlgebra( c );
 <algebra of dimension 0 over CF(5)>
 gap> Dimension( radc );
 0
+gap> Dimension( RadicalOfAlgebra( radc ) );
+0
 
 #############################################################################
 gap> cen:= Centralizer( c, GeneratorsOfAlgebra( c )[1] );