Dennis Courtney

most citedComposition Operators and Endomorphisms

7 citations · 10 across the 3 of their papers we have counts for

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3 papers · 1 filter

math.FA2010

A mini-max problem for self-adjoint Toeplitz matrices

Dennis Courtney, Donald Sarason

We study a minimum problem and associated maximum problem for finite, complex, self-adjoint Toeplitz matrices. If $A$ is such a matrix, of size $(N + 1)$ -by- $(N + 1)$ , we identify $A$ …

math.FA2010★ 7 cited

Composition Operators and Endomorphisms

Dennis Courtney, Paul S. Muhly, Samuel W. Schmidt

If $b$ is an inner function, then composition with $b$ induces an endomorphism, $β$ , of $L^{\infty} (T)$ that leaves $H^{\infty} (T)$ invariant. We investigate the stru…

math.FA2010★ 2 cited

Unions of arcs from Fourier partial sums

Dennis Courtney

Elementary complex analysis and Hilbert space methods show that a union of at most n arcs on the circle is uniquely determined by the nth Fourier partial sum of its characteristic…