U+22A5 Up Tack
U+22A5 was added in Unicode version 1.1 in 1993. It belongs to the block
This character is a Math Symbol and is commonly used, that is, in no specific script. The character is also known as base and bottom.
The glyph is not a composition. Its width in East Asian texts is determined by its context. It can be displayed wide or narrow. In bidirectional text it acts as Other Neutral. When changing direction it is not mirrored. If its East Asian Width is “narrow”, U+22A5 forms a word with similar characters, which prevents a line break inside it. Otherwise it allows line breaks around it, except in some numeric contexts. The glyph can be confused with one other glyph.
The CLDR project calls this character “up tack” for use in screen reading software. It assigns these additional labels, e.g. for search in emoji pickers: eet, falsum, tack.
The Wikipedia has the following information about this codepoint:
The up tack or falsum (⊥,
ot
in LaTeX, U+22A5 in Unicode) is a constant symbol used to represent:
 The truth value 'false', or a logical constant denoting a proposition in logic that is always false (often called "falsum" or "absurdum").
 The bottom element in wheel theory and lattice theory, which also represents absurdum when used for logical semantics
 The bottom type in type theory, which is the bottom element in the subtype relation. This may coincide with the empty type, which represents absurdum under the Curry–Howard correspondence
 The "undefined value" in quantum physics interpretations that reject counterfactual definiteness, as in (r_{0},⊥)
as well as
 Mixed radix decoding in the APL programming language
The glyph of the up tack appears as an upsidedown tee symbol, and as such is sometimes called eet (the word "tee" in reverse). Tee plays a complementary or dual role in many of these theories.
The similarlooking perpendicular symbol (⟂,
perp
in LaTeX, U+27C2 in Unicode) is a binary relation symbol used to represent:
 Perpendicularity of lines in geometry
 Orthogonality in linear algebra
 Independence of random variables in probability theory
 Coprimality in number theory
The double tack up symbol (⫫, U+2AEB in Unicode) is a binary relation symbol used to represent:
 Conditional independence of random variables in probability theory
Representations
System  Representation 

Nº  8869 
UTF8  E2 8A A5 
UTF16  22 A5 
UTF32  00 00 22 A5 
URLQuoted  %E2%8A%A5 
HTML hex reference  ⊥ 
Wrong windows1252 Mojibake  âŠ¥ 
HTML named entity  ⊥ 
HTML named entity  ⊥ 
HTML named entity  ⊥ 
HTML named entity  ⊥ 
alias  base 
alias  bottom 
Encoding: EUCKR (hex bytes)  A1 D1 
Encoding: JIS0208 (hex bytes)  A2 DD 
Encoding: JIS0208 (hex bytes)  AD F6 
L^{A}T_{E}X  \perp 
Adobe Glyph List  perpendicular 
digraph  T 
Related Characters
Confusables
Elsewhere
Complete Record
Property  Value 

1.1 (1993)  
UP TACK  
—  
Mathematical Operators  
Math Symbol  
Common  
Other Neutral  
Not Reordered  
none  


✘  




✘  










✘  
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✘  
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Any  
✔  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
✘  
0  
0  
0  
✘  
None  
—  
NA  
Other  
—  
✘  
✘  
✔  
✘  
Yes  
Yes  


Yes  


Yes  
✘  
✘  
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✔  
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Other  
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Other  
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✘  
✘  
✘  
✘  


None  
ambiguous  
Not Applicable  
—  
No_Joining_Group  
Non Joining  
Ambiguous (Alphabetic or Ideographic)  
none  
not a number  


R 