Definition:P-Sequence Space
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Definition
Let $p \in \R$, $p \ge 1$.
The $p$-sequence space, denoted $\ell^p$ or $\map {\ell^p} \N$, is defined as:
- $\ds \ell^p := \set {\sequence {z_n}_{n \mathop \in \N} \in \C^\N: \sum_{n \mathop = 0}^\infty \size {z_n}^p < \infty}$
As such, $\ell^p$ is a subspace of $\C^\N$, the space of all complex sequences.
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Also defined as
Authors coming from the direction of measure theory often define $\ell^p$ as consisting of real sequences.
To explicate the base field, $\ell^p_\R$ and $\ell^p_\C$ may be used.
Also known as
Some authors call the sequence space the Lebesgue space, but this term is reserved for a more general object on $\mathsf{Pr} \infty \mathsf{fWiki}$.
Also see
- Definition:Hilbert Sequence Space
- Definition:Lebesgue Space
- $p$-Sequence Space is Lebesgue Space
- Definition:Space of Bounded Sequences
- Results about $p$-sequence spaces can be found here.
Sources
- 2005: René L. Schilling: Measures, Integrals and Martingales ... (previous) ... (next): $12.12$
- 2017: Amol Sasane: A Friendly Approach to Functional Analysis ... (previous) ... (next): Chapter $1.1$: Normed and Banach spaces. Vector Spaces