# Definition:Rubik's Cube/Center Facet

< Definition:Rubik's Cube(Redirected from Definition:Center Facet of Rubik's Cube)

## Definition

Of each of the $9$ facets of each face of Rubik's cube, the ones in the centers of the faces are called the **center facets**.

The set of **center facets** can be denoted $S_Z$.

The set of **center facets** is:

- $S_Z = \set {F, U, R, L, B, D}$

## Linguistic Note

In the notation $S_Z$ for the **center facets of Rubik's cube**, the subscript $Z$ is for **zentrum**, which is German for **center**.

$C$ cannot be used, because $S_C$ is already in use as the symbol denoting the set of corner facets.

## Sources

- 2008: David Joyner:
*Adventures in Group Theory*(2nd ed.) ... (previous) ... (next): Chapter $1$: Elementary, my dear Watson: $\S 1.2$: Elements, my dear Watson: Example $1.2.3$