Direct and inverse results on row sequences of Hermite-Pad\'e   approximants
  We give necessary and sufficient conditions for the convergence with geometric rate of the common denominators of simultaneous rational interpolants with a bounded number of poles. The conditions are expressed in terms of intrinsic properties of the system of functions used to build the approximants. Exact rates of convergence for these denominators and the simultaneous rational approximants are provided. 
J. Cacoq, B. de la Calle Ysern, G. L\'opez Lagomasino
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