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Research output: Thesis › Doctoral Thesis
Research output: Thesis › Doctoral Thesis
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TY - BOOK
T1 - Generalisations of Pick's theorem to reproducing Kernel Hilbert spaces
AU - Quiggin, Peter Philip
PY - 1994
Y1 - 1994
N2 - Pick's theorem states that there exists a function in H1, which is bounded by 1and takes given values at given points, if and only if a certain matrix is positive.H1 is the space of multipliers of H2 and this theorem has a natural generalisationwhen H1 is replaced by the space of multipliers of a general reproducing kernelHilbert space H(K) (where K is the reproducing kernel). J. Agler showed that thisgeneralised theorem is true when H(K) is a certain Sobolev space or the Dirichletspace. This thesis widens Agler's approach to cover reproducing kernel Hilbertspaces in general and derives sucient (and usable) conditions on the kernel K,for the generalised Pick's theorem to be true for H(K). These conditions arethen used to prove Pick's theorem for certain weighted Hardy and Sobolev spacesand for a functional Hilbert space introduced by Saitoh. The reproducing kernelapproach is then used to derived results for several related problems. These includethe uniqueness of the optimal interpolating multiplier, the case of operator-valuedfunctions and a proof of the Adamyan-Arov-Kren theorem.
AB - Pick's theorem states that there exists a function in H1, which is bounded by 1and takes given values at given points, if and only if a certain matrix is positive.H1 is the space of multipliers of H2 and this theorem has a natural generalisationwhen H1 is replaced by the space of multipliers of a general reproducing kernelHilbert space H(K) (where K is the reproducing kernel). J. Agler showed that thisgeneralised theorem is true when H(K) is a certain Sobolev space or the Dirichletspace. This thesis widens Agler's approach to cover reproducing kernel Hilbertspaces in general and derives sucient (and usable) conditions on the kernel K,for the generalised Pick's theorem to be true for H(K). These conditions arethen used to prove Pick's theorem for certain weighted Hardy and Sobolev spacesand for a functional Hilbert space introduced by Saitoh. The reproducing kernelapproach is then used to derived results for several related problems. These includethe uniqueness of the optimal interpolating multiplier, the case of operator-valuedfunctions and a proof of the Adamyan-Arov-Kren theorem.
M3 - Doctoral Thesis
PB - Lancaster University
CY - Lancaster
ER -