Differential Operator Sub-product Of Sex-linked

In this paper we discuss the boundary conditions for the selfadjointness of the ordinary differential operators.Let L, = D* + q(f) , where q e C4 , / = 1,2 , with different domains, we have1. On [0,oo) the product L = L2Lt of operator Z,j and L2 isselfadjointifandonly ifwhere 4 5, C, ? are some ordinary matrix with Rank (A B)=Rank (C D)=4.2. On [0,w) the square Z/j of operator L{ is selfadjoint if and only ifZ-jisselfadjoint and BH4B* = 0 .3. On [a,b] the product L = L2 Lt of operator L{ and L2 is selfadjoint if and only if4. On [a,b] the square Z,, of operator Lx is selfadjoint, if and only if Z<, is selfadjiont. If L, (1=1,2,3) are S-T operators we have the following.5. On [a,b] the product L = L3L2L{ of operator LltL2 and L3 is selfadjoint if andonly if A and L2 is selfadjoint.6. On [a,b] the third power L^ of operator Z,j is selfadjoint if and only if L^ isselfadjoint.