U+22A5 Up Tack
U+22A5 was added in Unicode version 1.1 in 1993. It belongs to the block Mathematical Operators in the Basic Multilingual Plane.
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, up.
The Wikipedia has the following information about this codepoint:
The up tack or falsum (⊥,
otin 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 (r0,⊥)
as well as
- Mixed radix decoding in the APL programming language
The glyph of the up tack appears as an upside-down 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 similar-looking perpendicular symbol (⟂,
perpin 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 |
| UTF-8 | E2 8A A5 |
| UTF-16 | 22 A5 |
| UTF-32 | 00 00 22 A5 |
| URL-Quoted | %E2%8A%A5 |
| HTML hex reference | ⊥ |
| Wrong windows-1252 Mojibake | ⊥ |
| HTML named entity | ⊥ |
| HTML named entity | ⊥ |
| HTML named entity | ⊥ |
| HTML named entity | ⊥ |
| alias | base |
| alias | bottom |
| Encoding: BIG5 (hex bytes) | A1 E6 |
| Encoding: BIG5HKSCS (hex bytes) | A1 E6 |
| Encoding: CP932 (hex bytes) | 81 DB |
| Encoding: CP949 (hex bytes) | A1 D1 |
| Encoding: CP950 (hex bytes) | A1 E6 |
| Encoding: EUC_JP (hex bytes) | A2 DD |
| Encoding: EUC_JIS_2004 (hex bytes) | A2 DD |
| Encoding: EUC_JISX0213 (hex bytes) | A2 DD |
| Encoding: EUC_KR (hex bytes) | A1 D1 |
| Encoding: GB2312 (hex bytes) | A1 CD |
| Encoding: GBK (hex bytes) | A1 CD |
| Encoding: GB18030 (hex bytes) | A1 CD |
| Encoding: HZ (hex bytes) | 7E 7B 21 4D 7E 7D |
| Encoding: ISO2022_JP (hex bytes) | 1B 24 42 22 5D 1B 28 42 |
| Encoding: ISO2022_JP_1 (hex bytes) | 1B 24 42 22 5D 1B 28 42 |
| Encoding: ISO2022_JP_2 (hex bytes) | 1B 24 42 22 5D 1B 28 42 |
| Encoding: ISO2022_JP_2004 (hex bytes) | 1B 24 42 22 5D 1B 28 42 |
| Encoding: ISO2022_JP_3 (hex bytes) | 1B 24 42 22 5D 1B 28 42 |
| Encoding: ISO2022_JP_EXT (hex bytes) | 1B 24 42 22 5D 1B 28 42 |
| Encoding: ISO2022_KR (hex bytes) | 1B 24 29 43 0E 21 51 0F |
| Encoding: JOHAB (hex bytes) | D9 61 |
| Encoding: SHIFT_JIS (hex bytes) | 81 DB |
| Encoding: SHIFT_JIS_2004 (hex bytes) | 81 DB |
| Encoding: SHIFT_JISX0213 (hex bytes) | 81 DB |
| LATEX | \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 | |
| Up Tack | |
| ✘ | |
| Up Tack | |
| Up Tack | |
| ✘ | |
| Up Tack | |
| Up Tack | |
| Up Tack | |
| Up Tack | |
| Up Tack | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| Up Tack | |
| Any | |
| ✔ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| 0 | |
| 0 | |
| 0 | |
| ✘ | |
| None | |
| — | |
| NA | |
| Other | |
| — | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✔ | |
| ✘ | |
| Yes | |
| Yes | |
| Up Tack | |
| Yes | |
| Up Tack | |
| Yes | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✔ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| Other | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| Other | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| ✘ | |
| Up Tack | |
| None | |
| ambiguous | |
| Not Applicable | |
| — | |
| No_Joining_Group | |
| Non Joining | |
| Ambiguous (Alphabetic or Ideographic) | |
| none | |
| not a number | |
| Up Tack | |
| R |