Negated Operators

Sometimes you need to enter a negated operator like ≠. If you’re a C/C++ programmer, you might think that != should map to ≠, since that’s what != means in those languages (and some others). But since in mathematics ! means factorial, this choice is a bad idea for inputting ≠ into mathematical text. You can type in \ne to get ≠, but there’s the simpler combination: /=. In the linear format used in Microsoft Office math, / is used for “stacked” fractions. But /= building up to a fraction with an empty denominator followed by an equal sign isn’t very useful. Also if you really want such a fraction, you can get it by typing /<space>.

Accordingly in Office 2010 math entry, /= builds up to ≠. This approach can be used to input many other negated operators as listed in the following table

Operator	Negated op	Input
<	≮	/<
=	≠	/=
>	≯	/>
∃	∄	/\exists
∈	∉	/\in
∋	∌	/\ni
∼	≁	/\sim
≃	≄	/\simeq
≅	≇	/\cong
≈	≉	/\approx
≍	≭	/\asymp
≡	≢	/\equiv
≤	≰	/\le
≥	≱	/\ge
≶	≸	/\lessgtr
≷	≹	/\gtrless
≽	⋡	/\succeq
≺	⊀	/\prec
≻	⊁	/\succ
≼	⋠	/\preceq
⊂	⊄	/\subset
⊃	⊅	/\supset
⊆	⊈	/\subseteq
⊇	⊉	/\supseteq
⊑	⋢	/\sqsubseteq
⊒	⋣	/\sqsupseteq

All of these operators are in the U+2200 Unicode block (Mathematical Operators) except for the ASCII characters <, =, and >. TeX has a similar, but more verbose approach that uses the control word \not followed by the name of the operator. For example, in TeX, \not\exists produces ∄.

Note that if you don’t like an automatic translation when entering math, you can undo the translation by typing ctrl+z. This way of entering negated operators along with some other extensions to the linear format will be documented in a future version of Unicode Technical Note #28.