Definition:Rubik's Cube/Corner Facet

Definition

 * RubiksCubeFacets.png

Of each of the $9$ facets of each face of Rubik's cube, the $4$ in the corners of the face are called the corner facets.

The set of corner facets can be denoted $S_C$.

For example:
 * $flu$, $fru$, $frd$, $fld$ are the corner facets of the front face
 * $ulb$, $urb$, $urf$, $ulf$ are the corner facets of the up face

and so on.