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Polynomial sequences generated by infinite Hessenberg matrices

Luis Verde-Star (2017)

Special Matrices

We show that an infinite lower Hessenberg matrix generates polynomial sequences that correspond to the rows of infinite lower triangular invertible matrices. Orthogonal polynomial sequences are obtained when the Hessenberg matrix is tridiagonal. We study properties of the polynomial sequences and their corresponding matrices which are related to recurrence relations, companion matrices, matrix similarity, construction algorithms, and generating functions. When the Hessenberg matrix is also Toeplitz...

Remark on the inequality of F. Riesz

W. Łenski (2005)

Banach Center Publications

We prove F. Riesz’ inequality assuming the boundedness of the norm of the first arithmetic mean of the functions | φ | p with p ≥ 2 instead of boundedness of the functions φₙ of an orthonormal system.

Sharp estimates of the Jacobi heat kernel

Adam Nowak, Peter Sjögren (2013)

Studia Mathematica

The heat kernel associated with the setting of the classical Jacobi polynomials is defined by an oscillatory sum which cannot be computed explicitly, in contrast to the situation for the other two classical systems of orthogonal polynomials. We deduce sharp estimates giving the order of magnitude of this kernel, for type parameters α, β ≥ -1/2. Using quite different methods, Coulhon, Kerkyacharian and Petrushev recently also obtained such estimates. As an application of the bounds, we show that...

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