Examples of Plentiful Discrete Spectra in0 Infinite Spatial Cruciform   Quantum Waveguides
  Spatial cruciform quantum waveguides (the Dirichlet problem for Laplace operator) are constructed such that the total multiplicity of the discrete spectrum exceeds any preassigned number. 
F.L. Bakharev, S. G. Matveenko, S.A. Nazarov
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