decomposing boundary triplet we examine separated boundary conditions of various classes. Recall that self-adjoint separated boundary conditions for definite Hamiltonian systems were studied with the aid of analytic methods by many authors (see [@HinSch93; @Kra89] and references therein). In the present paper we show that self-adjoint separated boundary conditions for the definite canonical system exist if and only if this system is Hamiltonian. Moreover, for the Hamiltonian system the decomposing boundary triplet $\bt$ for $\Tma$ takes the form $$\begin{gathered}
\G_0 \{\wt y, \wt f\} =\{ y_0(a),\, \G_{0b}y \} (\in H\oplus \cH_b),\qquad \G_1
\{\wt y, \wt f\} = \{ y_1(a),\, -\G_{1b}y \}(\in H \oplus \cH_b), \quad \{\wt
y, \wt f\} \in \Tma\end{gathered}$$ and the general form of self-adjoint separated boundary conditions is $$\begin{gathered}
\label{1.26}
\wt A=\{\{\wt y, \wt f\}:\, N_{0a}y_0(a)+N_{1a}y_1(a)=0, \;\;
N_{0b}\G_{0b}y+N_{1b}\G_{1b}y=0 \},\end{gathered}$$ where the operators $N_{0a},\; N_{1a}$ and $N_{0b},\; N_{1b}$ are entries of the self-adjoint operator pairs $\{(N_{0a}, N_{1a})\}$ and $\{(N_{0b},
N_{1b})\}$. These results are generalizations of those obtained by Rofe-Beketov in [@Rof69] for regular differential operators. Moreover, formula includes as a particular case the results on self-adjoint separated boundary conditions in [@HinSch93; @Kra89].

An interesting in our opinion fact is the existence of maximal dissipative an accumulative separated boundary 