Abstract:
Symmetric block Jacobi matrices $J$ and the corresponding
symmetric operators $L$ are studied. Let $m$ be the size of the blocks in the matrix $J$.
As is known, the deficiency numbers $m_+$ and $m_-$ of the operator $L$
satisfy the inequalities $0\leqslant m_+,m_-\leqslant m$ and achieve their maximum value $m$ simultaneously. Let $m_+$ and $m_-$ be arbitrary integers such that
$0\leqslant m_+,m_-\leqslant m-1$.
It is shown that there exists a symmetric Jacobi matrix $J$ such that $m_+$
and $m_-$ are the deficiency numbers of the corresponding symmetric operator $L$.
Bibliography: 13 titles.