Tee (symbol) explained

The tee (⊤, \top in LaTeX), also called down tack (as opposed to the up tack) or verum,^[1] is a symbol used to represent:

• The top element in lattice theory.
• The truth value of being true in logic, or a sentence (e.g., formula in propositional calculus) which is unconditionally true.^{[2] [3] [4]} By definition, every tautology is logically equivalent to the verum.
• The top type in type theory.
• Mixed radix encoding in the APL programming language.
• A lowered phonic in the International Phonetic Alphabet and phonetics. In this usage, it is usually written under the primary IPA symbol.

A similar-looking superscript T may be used to mean the transpose of a matrix.

Encoding

In Unicode, the tee character is encoded as .^[5] The symbol is encoded in LaTeX as \top.

A large variant is encoded as in the Unicode block Miscellaneous Mathematical Symbols-A.

See also

• Turnstile (⊢)
• Up tack (⊥)
• List of logic symbols
• List of mathematical symbols

Notes and References

1. Polkowski . Lech T. . 2023 . Logic: Reference Book for Computer Scientists . Intelligent Systems Reference Library . 245 . 180 . 10.1007/978-3-031-42034-4 . 978-3-031-42033-7 . 1868-4394.
2. Web site: tautology Definition & Facts . Encyclopedia Britannica . en . 2020-08-14.
3. Web site: Definition of TAUTOLOGY . en . www.merriam-webster.com . 2020-08-14.
4. Web site: Weisstein . Eric W. . Tautology . en . mathworld.wolfram.com . 2020-08-14.
5. Web site: Mathematical Operators – Unicode . 2013-07-20.