# Definition:Hilbert Cube

## Definition

The Hilbert cube $\struct {I^\omega, d_2}$ is the subspace of the Hilbert sequence space $I^\omega$ defined as:

$\displaystyle I^\omega = \prod_{k \mathop \in \N} \closedint 0 {\dfrac 1 k}$

under the same metric as that of the Hilbert sequence space:

$\displaystyle \forall x = \sequence {x_i}, y = \sequence {y_i} \in I^\omega: \map {d_2} {x, y} := \paren {\sum_{k \mathop \ge 0} \paren {x_k - y_k}^2}^{\frac 1 2}$

## Also see

• Results about the Hilbert cube can be found here.

## Source of Name

This entry was named for David Hilbert.