Approximations of permutation-symmetric vertex couplings in quantum graphs
نویسندگان
چکیده
We consider boundary conditions at the vertex of a star graph which make Schrödinger operators on the graph self-adjoint, in particular, the two-parameter family of such conditions invariant with respect to permutations of graph edges. It is proved that the corresponding operators can be approximated in the norm-resolvent sense by elements of another Schrödinger operator family on the same graph in which the δ coupling is imposed at the vertex and an additional point interaction is placed at each edge provided the coupling parameters are properly chosen.
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