Szeg\H{o}'s theorem for matrix orthogonal polynomials
  We extend some classical theorems in the theory of orthogonal polynomials on the unit circle to the matrix case. In particular, we prove a matrix analogue of Szeg\H{o}'s theorem. As a by-product, we also obtain an elementary proof of the distance formula by Helson and Lowdenslager. 
Maxim Derevyagin, Olga Holtz, Sergey Khrushchev, Mikhail Tyaglov
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