Definition:Proper Subset/Also known as

Proper Subset: Also known as
$S \subsetneqq T$ can also be read as:
 * $S$ is properly included in $T$, or $T$ properly includes $S$
 * $S$ is strictly included in $T$, or $T$ strictly includes $S$

The following usage can also be seen for $S \subsetneqq T$:


 * $S$ is properly contained in $T$, or $T$ properly contains $S$
 * $S$ is strictly contained in $T$, or $T$ strictly contains $S$

However, beware of the usage of contains: $S$ contains $T$ can also be interpreted as $S$ is an element of $T$.

Hence the use of contains is not supported on.