name of logical negation symbol ¬

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How to look up a symbol?

The instructor of a statistics and probability course uses an odd (to me) symbol for logical negation. The symbol is not a tide (~) or an exclamation mark (!) or the bar-over symbol. This symbol looks like the top right hand corner of a rectangle. What is this symbol called?

Welcome to TeX.sx! Could you upload a sketch of this symbol to help us identify it, please? As new user without image posting privileges simply include the image as normal and remove the ! in front of it to turn it into a link. A moderator or another user with edit privileges can then reinsert the ! to turn it into an image again. — diabonas, Jul 23 '12 at 18:13
You're looking for $\neg$ ; for more symbols, see How to look up a symbol? — Werner, Jul 23 '12 at 18:14
@Werner Do I need to load a package to have access to \neg? — a06e, Mar 27 '23 at 09:52
@a06e: No, \neg is available by default. You can try with this code, which should compile without problem and yield ¬x. — Werner, Mar 27 '23 at 16:15

score 44 · Answer 1 · answered Jul 23 '12 at 18:17

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I have seen that symbol rather frequently and is a popular mathematical notation. AFAIK ~ and ! are more popular in computer science/engineering, because there is an actual symbol for that on the keyboard. :) The symbol is defined in math mode as \neg.

answered Jul 23 '12 at 18:17

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As a character, it’s “¬” U+00AC NOT SIGN, and it’s the standard symbol for negation in logic and mathematics (most recently, as per the ISO 80000-2 standard, which does not even mention other notations for it). – Jukka K. Korpela Jul 23 '12 at 18:22
Actually UK keyboards have the ¬ symbol too. As does the US international keyboard layout (altgr + ""). So the reason other symbols are more popular is because the normal US layout is more common. – jiggunjer Jun 21 '16 at 07:01

name of logical negation symbol ¬

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