From 95066b9c5651e6edd539d2170db9e82393a95685 Mon Sep 17 00:00:00 2001
From: kalmarek <kalmar@amu.edu.pl>
Date: Sat, 18 Aug 2018 23:23:52 +0200
Subject: [PATCH] fix the action of WreathProdElem on MatElem

mul! is not correct for NmodRing??
---
 groups/speciallinear.jl | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/groups/speciallinear.jl b/groups/speciallinear.jl
index f02760f..98e560c 100644
--- a/groups/speciallinear.jl
+++ b/groups/speciallinear.jl
@@ -10,8 +10,8 @@ struct SpecialLinearGroup <: SymmetrizedGroup
         if p == 0
             G = MatrixSpace(Nemo.ZZ, n, n)
         else
-            F, a = FiniteField(p, 1, "a")
-            G = MatrixSpace(F, n, n)
+            R = Nemo.NmodRing(UInt(p))
+            G = MatrixSpace(R, n, n)
         end
         return new(args, G)
     end
@@ -83,9 +83,7 @@ function (g::WreathProductElem)(A::MatElem)
     G = matrix_emb(g.n, g_inv.p)
     G_inv = matrix_emb(g_inv.n, g.p)
     M = parent(A)
-    res = M(G_inv)
-    Nemo.mul!(res, A, res)
-    return Nemo.mul!(res, M(G), res)
+    return M(G)*A*M(G_inv)
 end
 
 import Base.*
@@ -100,7 +98,7 @@ function *(x::AbstractAlgebra.MatElem, P::Generic.perm)
    n = cols(x)
    for i = 1:m
       for j = 1:n
-         z[i, j] = x[i, P[j]]
+         z[i, j] = x[i,P[j]]
       end
    end
    return z