Ǥϡ֤ΤνޤפֽפȤ
֤ΤΤĤޤפǤ뽸͡νͤ˴ޤޤΤ(element)Ȥ
ϡΤ褦ɽ롣 \[ \in \]
\(\in\) Ȥϡ(element)Ρeפ뤤ϡꥷΡ֦šפͳ褹Ȥ롣
ΤΤνޤǤ뽸ȤƽͤȽΤȤͤΣģĤΤΡʡǡˤΤΣģĤбȤͤȽΤƱ礭ĤȤ
ΤȤͤȽΤƱǻ(cardinality)ĤȤ
ΤǤɬͤǤˤʤäƤϽȤƣΤϣͤ˴ޤޤȤΤϣͤʬǤȤ \[ \subset \]