 Conway's notation itself avoids Coxeter's alternation (half) operation since it only applies for polyhedra with only even-sided faces.In 4-dimensions, Conway suggests the snub 24-cell should be called a "semi-snub 24-cell" because it doesn't represent an alternated omnitruncated 24-cell like his 3-dimensional polyhedron usage.It is instead actually an alternated truncated 24-cell.