# Symbols:Set Theory/Deprecated Symbols

## Deprecated Symbols of Set Theory

This page contains symbols which may or may not be in current use, but are either non-standard in mathematics or have been superseded by their more modern variants.

However, on $\mathsf{Pr} \infty \mathsf{fWiki}$ the intention is to present a consistent style, and so these symbols are to be considered deprecated.

### Subset

$\subset$ is sometimes used to mean:

$S$ is a subset of $T$

in the sense that $S$ is permitted to equal $T$.

That is, for which we have specified as $S \subseteq T$.

Although many sources use this interpretation, it is emphatically not recommended, as it can be the cause of considerable confusion.

### Superset

$\supset$ is sometimes used to mean:

$S$ is a superset of $T$

in the sense that $S$ is permitted to equal $T$.

That is, for which we have specified as $S \supseteq T$.

Although many sources use this interpretation, it is emphatically not recommended, as it can be the cause of considerable confusion.