Multiple Geronimus transformations
  We consider multiple Geronimus transformations and show that they lead to discrete (non-diagonal) Sobolev type inner products. Moreover, it is shown that every discrete Sobolev inner product can be obtained as a multiple Geronimus transformation. A connection with Geronimus spectral transformations for matrix orthogonal polynomials is also considered. 
Maxim Derevyagin, Juan Carlos Garc\'ia-Ardila, Francisco Marcell\'an
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