superdiagonal

English

Etymology

From super- +‎ diagonal.

Pronunciation

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Noun

superdiagonal (plural superdiagonals)

1. (mathematics) The diagonal of a matrix that lies directly above and to the right of the main diagonal.
   • 2016, Eric Evert, J. William Helton, Igor Klep, Scott McCullough, “Circular Free Spectrahedra”, in arXiv‎^[1]:

     We classify all free spectrahedra that are circular, that is, closed under multiplication by exp(i t): up to unitary equivalence, the coefficients of a minimal LMI defining a circular free spectrahedron have a common block decomposition in which the only nonzero blocks are on the superdiagonal.