Downloads provided by UsageCounts
handle: 2445/200873 , 10852/93947 , 10852/102666
A Hilbert point in H p ( T d ) H^p(\mathbb {T}^d) , for d ≥ 1 d\geq 1 and 1 ≤ p ≤ ∞ 1\leq p \leq \infty , is a nontrivial function φ \varphi in H p ( T d ) H^p(\mathbb {T}^d) such that ‖ φ ‖ H p ( T d ) ≤ ‖ φ + f ‖ H p ( T d ) \| \varphi \|_{H^p(\mathbb {T}^d)} \leq \|\varphi + f\|_{H^p(\mathbb {T}^d)} whenever f f is in H p ( T d ) H^p(\mathbb {T}^d) and orthogonal to φ \varphi in the usual L 2 L^2 sense. When p ≠ 2 p\neq 2 , φ \varphi is a Hilbert point in H p ( T ) H^p(\mathbb {T}) if and only if φ \varphi is a nonzero multiple of an inner function. An inner function on T d \mathbb {T}^d is a Hilbert point in any of the spaces H p ( T d ) H^p(\mathbb {T}^d) , but there are other Hilbert points as well when d ≥ 2 d\geq 2 . The case of 1 1 -homogeneous polynomials is studied in depth and, as a byproduct, a new proof is given for the sharp Khinchin inequality for Steinhaus variables in the range 2 > p > ∞ 2>p>\infty . Briefly, the dynamics of a certain nonlinear projection operator is treated. This operator characterizes Hilbert points as its fixed points. An example is exhibited of a function φ \varphi that is a Hilbert point in H p ( T 3 ) H^p(\mathbb {T}^3) for p = 2 , 4 p=2, 4 , but not for any other p p ; this is verified rigorously for p > 4 p>4 but only numerically for 1 ≤ p > 4 1\leq p>4 .
Hardy spaces, Mathematics - Complex Variables, Funcions de variables complexes, Espais de Hardy, Anàlisi harmònica, Functions of complex variables, Functional Analysis (math.FA), Harmonic analysis, Mathematics - Functional Analysis, Inequalities (Mathematics), Mathematics - Classical Analysis and ODEs, H-espaces, H-espais, Classical Analysis and ODEs (math.CA), FOS: Mathematics, Complex Variables (math.CV), Desigualtats (Matemàtica)
Hardy spaces, Mathematics - Complex Variables, Funcions de variables complexes, Espais de Hardy, Anàlisi harmònica, Functions of complex variables, Functional Analysis (math.FA), Harmonic analysis, Mathematics - Functional Analysis, Inequalities (Mathematics), Mathematics - Classical Analysis and ODEs, H-espaces, H-espais, Classical Analysis and ODEs (math.CA), FOS: Mathematics, Complex Variables (math.CV), Desigualtats (Matemàtica)
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 0 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Average | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Average | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Average |
| views | 80 | |
| downloads | 99 |

Views provided by UsageCounts
Downloads provided by UsageCounts