ๅ้ๅ
้ๅSใซๅๅค้ขไฟ$ \simใไธใใใใๆใๆฐใใ้ๅ $ S/{\sim} = \{ C(x) \in 2^S \mid x \in S\} \subset 2^S
ใๅฎ็พฉใใ
$ S/{\sim}ใๅๅค้ขไฟ$ \simใซใใๅ้ๅใจ่จใใ
ๅ้ๅใฏใๅๅค้ขไฟใซใใๅๅๅค้กใๅ
ใจใใๅช้ๅ$ 2^Sใฎ้จๅ้ๅใงใใ ๅ้ๅ