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

 * Hilbert Cube is Metric Space