[boost] is something seriously wrong with zero_vector?

I noticed that creating a zero_vector with some size, and then iterating over it produced strange results. Then I noticed this: BOOST_UBLAS_INLINE const_iterator begin () const { return const_iterator (*this); } BOOST_UBLAS_INLINE const_iterator end () const { return const_iterator (*this); } Excuse me? Doesn't this mean begin() == end() and effectively size is always zero?