Inequality symbol
There are four symbols conventionally used to represent the notion of inequality.
If and are real numbers we write:
- to mean that is strictly greater than (that is, cannot equal ).
- to mean that is greater than or equal to (equivalently, "at least as large as") .
- to mean that is strictly less than
- to mean that is less than or equal to .
We use a slash through an inequality symbol to represent that the given inequality does not hold. Thus for real numbers and ,
- if and only if
- if and only if
- if and only if
- if and only if
- if and only if or
These symbols are also frequently used to represent the order relation in a partially ordered set. Note that in this more general setting, it is not necessarily true that , because it is also possible that and could be incomparable.