4 papers
Optimal rates of decay in the Katznelson-Tzafriri theorem for operators on Hilbert spaces
Abraham C. S. Ng, David Seifert
The Katznelson-Tzafriri theorem is a central result in the asymptotic theory of discrete operator semigroups. It states that for a power-bounded operator on a Banach space we h…
Direct integrals of strongly continuous operator semigroups
Abraham C. S. Ng
The goal of this article is to develop a theory for direct integrals of -semigroups on Hilbert spaces parallel to the recent approach by Lachowicz and Moszyński for direct sum…
Optimal energy decay in a one-dimensional wave-heat-wave system
Abraham C. S. Ng
Harnessing the abstract power of the celebrated result due to Borichev and Tomilov (Math.\ Ann.\ 347:455--478, 2010, no.\ 2), we study the energy decay in a one-dimensional coupled…
Optimal energy decay in a one-dimensional wave-heat system with infinite heat part
Abraham C. S. Ng, David Seifert
Using recent results in the theory of -semigroups due to Batty, Chill and Tomilov (J. Eur. Math. Soc. 18(4):853-929, 2016) we study energy decay in a one-dimensional coupled w…