https://github.com/Singular/Singular/commit/d3f73432d73ac0dd041

diff --git a/src/gfanlib_matrix.h b/src/gfanlib_matrix.h
index 418fa4c..27818b2 100644
--- a/src/gfanlib_matrix.h
+++ b/src/gfanlib_matrix.h
@@ -115,6 +115,7 @@ public:
         	  p[i][j]=s*(q[i][j]);
       return p;
     }
+  /*
   friend Matrix operator*(const Matrix& a, const Matrix& b)
     {
       assert(a.width==b.height);
@@ -123,6 +124,7 @@ public:
         ret[i]=a.vectormultiply(b.column(i));
       return ret.transposed();
     }
+  */
   /*  template<class T>
     Matrix<T>(const Matrix<T>& c):v(c.size()){
     for(int i=0;i<size();i++)v[i]=typ(c[i]);}