From c8852dad5a63e5112574afca7cc31d56dcf714d5 Mon Sep 17 00:00:00 2001
From: bh11 <bh11@users.noreply.github.com>
Date: Sat, 9 Apr 2016 00:41:28 +0200
Subject: [PATCH] fix bug in NewmanInfinityCriterion trying to modify result of
 PCentralSeries

---
 lib/grpfp.gi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/grpfp.gi b/lib/grpfp.gi
index 6329a3ce4a..0c0c079e91 100644
--- a/lib/grpfp.gi
+++ b/lib/grpfp.gi
@@ -5242,7 +5242,7 @@ local GO,q,d,e,b,r,val,agemo,ngens;
     q:=PQuotient(G,p,2,ngens);
   until q<>fail;
   q:=Image(EpimorphismQuotientSystem(q));
-  q:=PCentralSeries(q,p);
+  q:=ShallowCopy(PCentralSeries(q,p));
   if Length(q)=1 then
     Error("Trivial <p> quotient");
   fi;