diff --git a/src/include/array/array_base.cc.h b/src/include/array/array_base.cc.h
index ca1f4f9..de82ef6 100644
--- a/src/include/array/array_base.cc.h
+++ b/src/include/array/array_base.cc.h
@@ -7,120 +7,6 @@
 
 namespace CNORXZ
 {
-    /******************************
-     *   CArrayBase (protected)   *
-     ******************************/
-
-    template <typename T>
-    template <class Index>
-    YIndex CArrayBase<T>::mkSliceIndex(const YIndex& yi, const Index& ind) const
-    {
-	// TODO: if ind.dim() < iy.dim: assume Null-Indices on missing positions;
-	static_assert(has_sub<Index>::value, "got non-mutliple index");
-	CXZ_ASSERT(yi.dim() == ind.dim(), "got index of incompatible dimension = "
-		   << ind.dim() << ", expected: " << yi.dim());
-	Vector<XIndexPtr> npack;
-	Vector<SizeT> nbs;
-	auto ypack = yi.pack();
-	auto ipack = ind.pack();
-	const auto& bs = yi.blockSizes();
-	if constexpr(has_static_sub<Index>::value){
-	    constexpr SizeT ID = index_dim<Index>::value;
-	    npack.reserve(ID);
-	    nbs.reserve(ID);
-	    iter<0,ID>( [&](auto i) {
-		const auto& ii1 = ypack[i];
-		const auto& ii2 = std::get<i>(ipack);
-		if(ii2->dim() != 0){
-		    npack.push_back( mkSliceIndex(ii1, ii2) );
-		    nbs.push_back(bs[i]);
-		}
-	    }, NoF {} );
-	}
-	else {
-	    const SizeT idim = ind.dim();
-	    npack.reserve(idim);
-	    nbs.reserve(idim);
-	    for(SizeT i = 0; i != idim; ++i){
-		const auto& ii1 = ypack[i];
-		const auto& ii2 = ipack[i];
-		if(ii2->dim() != 0){
-		    npack.push_back( mkSliceIndex(ii1, ii2) );
-		    nbs.push_back(bs[i]);
-		}
-	    }
-	}
-	return yindex(npack);
-    }
-    
-    template <typename T>
-    template <class Index>
-    XIndexPtr CArrayBase<T>::mkSliceIndex(const XIndexPtr& xi, const Sptr<Index>& ind) const
-    {
-	// TODO: if ind.dim() < iy.dim: assume Null-Indices on missing positions;
-	CXZ_ASSERT(xi->dim() == ind->dim(), "got index of incompatible dimension = "
-		   << ind->dim() << ", expected: " << xi->dim());
-	Vector<XIndexPtr> npack;
-	Vector<SizeT> nbs;
-	auto xpack = xi->pack();
-	const auto& bs = xi->blockSizes();
-	if constexpr(has_static_sub<Index>::value){
-	    auto ipack = ind->pack();
-	    constexpr SizeT ID = index_dim<Index>::value;
-	    npack.reserve(ID);
-	    nbs.reserve(ID);
-	    iter<0,ID>( [&](auto i) {
-		const auto& ii1 = xpack[i];
-		const auto& ii2 = std::get<i>(ipack);
-		const XIndexPtr si = mkSliceIndex(ii1, ii2);
-		if(si != nullptr){
-		    npack.push_back( si );
-		    nbs.push_back(bs[i]);
-		}
-	    }, NoF {} );
-	}
-	else if constexpr(has_static_sub<Index>::value){
-	    auto ipack = ind->pack();
-	    const SizeT idim = ind->dim();
-	    const SizeT xdim = xi->dim();
-	    const SizeT isize = ipack.size();
-	    const SizeT xsize = xpack.size();
-	    if(isize == 0 or xsize == 0){
-		if(idim == 0){
-		    return xi->copy();
-		}
-		else {
-		    return nullptr;
-		}
-	    }
-	    CXZ_ASSERT(isize == idim and xsize == xdim, "index error");
-	    npack.reserve(idim);
-	    nbs.reserve(idim);
-	    for(SizeT i = 0; i != idim; ++i){
-		const auto& ii1 = xpack[i];
-		const auto& ii2 = ipack[i];
-		const XIndexPtr si = mkSliceIndex(ii1, ii2);
-		if(si != nullptr){
-		    npack.push_back( si );
-		    nbs.push_back(bs[i]);
-		}
-	    }
-	}
-	else {
-	    const SizeT idim = ind->dim();
-	    if(idim == 0){
-		return xi->copy();
-	    }
-	    else {
-		return nullptr;
-	    }
-	}
-	if(npack.size() == 0){
-	    return nullptr;
-	}
-	return xindexPtr(yindexPtr(npack));
-    }
-
     /******************
      *   CArrayBase   *
      ******************/
@@ -154,11 +40,10 @@ namespace CNORXZ
     template <typename I, typename M>
     Sptr<CArrayBase<T>> CArrayBase<T>::sl(const IndexInterface<I,M>& i) const
     {
-	auto beg = this->begin();
-	auto si = mkSliceIndex(beg, i);
-	auto it = beg + i.lex();
-	return std::make_shared<CSlice>(this, si, it.pos());
-	//return std::make_shared<CSlice>();
+	auto beg = std::make_shared<const_iterator>(this->begin());
+	auto si = i.slice(beg);
+	auto it = *beg + i.lex();
+	return std::make_shared<CSlice>(this, *si, it.pos());
     }
 
     template <typename T>
@@ -189,32 +74,16 @@ namespace CNORXZ
     template <class I, typename M>
     COpRoot<T,I> CArrayBase<T>::operator()(const IndexPtr<I,M>& i) const
     {
-	CXZ_ASSERT(false, "BLOCKSIZES!!");
-	return COpRoot<T,I>(*this, std::static_pointer_cast<I>(i));
+	auto fi = this->cbegin().format( std::static_pointer_cast<I>(i) );
+	return COpRoot<T,I>(*this, fi);
     }
 
     template <typename T>
     template <class I, SizeT L>
-    COpRoot<T,I> CArrayBase<T>::operator()(const LIndex<I,L>& i) const
+    COpRoot<T,I> CArrayBase<T>::operator()(const Sptr<LIndex<I,L>>& i) const
     {
-	CXZ_ASSERT(false, "BLOCKSIZES!!");
-	return COpRoot<T,LIndex<I,L>>(*this, i);
-    }
-
-    template <typename T>
-    template <class I, typename M>
-    COpRoot<T,I> CArrayBase<T>::op(const IndexPtr<I,M>& i) const
-    {
-	CXZ_ASSERT(false, "IMPLEMENT CHECKS!!");
-	return COpRoot<T,I>(*this, std::static_pointer_cast<I>(i));
-    }
-
-    template <typename T>
-    template <class I, SizeT L>
-    COpRoot<T,I> CArrayBase<T>::op(const LIndex<I,L>& i) const
-    {
-	CXZ_ASSERT(false, "IMPLEMENT CHECKS!!");
-	return COpRoot<T,LIndex<I,L>>(*this, i);
+	auto fi = this->cbegin().format( i );
+	return COpRoot<T,LIndex<I,L>>(*this, fi);
     }
 
     /*****************
@@ -248,11 +117,10 @@ namespace CNORXZ
     template <typename I, typename M>
     Sptr<ArrayBase<T>> ArrayBase<T>::sl(const IndexInterface<I,M>& i)
     {
-	auto r = mkSliceRange(i);
-	auto beg = this->begin();
-	auto bs = mkSliceBlockSizes(i, beg);
-	auto it = beg + i.lex();
-	return std::make_shared<Slice>(r, this, bs, it.pos());
+	auto beg = std::make_shared<const_iterator>(this->cbegin());
+	auto si = i.slice(beg);
+	auto it = *beg + i.lex();
+	return std::make_shared<Slice>(this, *si, it.pos());
     }
 
     template <typename T>
@@ -269,35 +137,20 @@ namespace CNORXZ
 
     template <typename T>
     template <class I, typename M>
-    OpRoot<T,I> ArrayBase<T>::operator()(const IndexPtr<I,M>& i) const
+    OpRoot<T,I> ArrayBase<T>::operator()(const IndexPtr<I,M>& i)
     {
-	CXZ_ASSERT(false, "BLOCKSIZES!!");
-	return OpRoot<T,I>(*this, std::static_pointer_cast<I>(i));
+	auto fi = this->cbegin().format( std::static_pointer_cast<I>(i) );
+	return OpRoot<T,I>(*this, fi);
     }
 
     template <typename T>
     template <class I, SizeT L>
-    OpRoot<T,I> ArrayBase<T>::operator()(const LIndex<I,L>& i) const
+    OpRoot<T,I> ArrayBase<T>::operator()(const Sptr<LIndex<I,L>>& i)
     {
-	CXZ_ASSERT(false, "BLOCKSIZES!!");
-	return OpRoot<T,LIndex<I,L>>(*this, i);
+	auto fi = this->cbegin().format( i );
+	return OpRoot<T,LIndex<I,L>>(*this, fi);
     }
 
-    template <typename T>
-    template <class I, typename M>
-    OpRoot<T,I> ArrayBase<T>::op(const IndexPtr<I,M>& i) const
-    {
-	CXZ_ASSERT(false, "IMPLEMENT CHECKS!!");
-	return OpRoot<T,I>(*this, std::static_pointer_cast<I>(i));
-    }
-
-    template <typename T>
-    template <class I, SizeT L>
-    OpRoot<T,I> ArrayBase<T>::op(const LIndex<I,L>& i) const
-    {
-	CXZ_ASSERT(false, "IMPLEMENT CHECKS!!");
-	return OpRoot<T,LIndex<I,L>>(*this, i);
-    }
 }
 
 #endif
diff --git a/src/include/array/array_base.h b/src/include/array/array_base.h
index ae552cc..741a744 100644
--- a/src/include/array/array_base.h
+++ b/src/include/array/array_base.h
@@ -21,12 +21,6 @@ namespace CNORXZ
 
     protected:
 	RangePtr mRange;
-
-	template <class Index>
-	YIndex mkSliceIndex(const YIndex& yi, const Index& i) const;
-
-	template <class Index>
-	XIndexPtr mkSliceIndex(const XIndexPtr& xi, const Sptr<Index>& i) const;
 	
     public:
 
@@ -59,13 +53,8 @@ namespace CNORXZ
 	COpRoot<T,I> operator()(const IndexPtr<I,M>& i) const;
 
 	template <class I, SizeT L>
-	COpRoot<T,I> operator()(const LIndex<I,L>& i) const;
+	COpRoot<T,I> operator()(const Sptr<LIndex<I,L>>& i) const;
 
-    	template <class I, typename M>
-	COpRoot<T,I> op(const IndexPtr<I,M>& i) const;
-
-	template <class I, SizeT L>
-	COpRoot<T,I> op(const LIndex<I,L>& i) const;
     };
 
     template <typename T>
@@ -103,16 +92,11 @@ namespace CNORXZ
 	virtual iterator end();
 	
 	template <class I, typename M>
-	OpRoot<T,I> operator()(const IndexPtr<I,M>& i) const;
+	OpRoot<T,I> operator()(const IndexPtr<I,M>& i);
 
 	template <class I, SizeT L>
-	OpRoot<T,I> operator()(const LIndex<I,L>& i) const;
+	OpRoot<T,I> operator()(const Sptr<LIndex<I,L>>& i);
 
-    	template <class I, typename M>
-	OpRoot<T,I> op(const IndexPtr<I,M>& i) const;
-
-	template <class I, SizeT L>
-	OpRoot<T,I> op(const LIndex<I,L>& i) const;
     };
 
 }