Turned A
Turned A (capital: Ɐ, lowercase: ɐ, math symbol ∀) is a letter and symbol based upon the letter A.
Modern usage
- Lowercase ɐ (in Roman or two story form) is used in the International Phonetic Alphabet to identify the near-open central vowel. This is not to be confused with the turned alpha or turned script a, ɒ, which is used in the IPA for the open back rounded vowel.[1]
- The logical symbol ∀, has the same shape as a turned E notation for existential quantification and the later use of Peano's notation by Bertrand Russell.[2]
Historical usage
-
Turned a presented in Edward Lhuyd's Archaeologia Britannica, 1707. -
Turned a in William Pryce's Archaeologia Cornu-Britannica, 1790.
It was used in the 18th century by Edward Lhuyd and William Pryce as a phonetic character for the Cornish language. In their books, both Ɐ and ɐ have been used.[3] It was used in the 19th century by Charles Sanders Peirce as a logical symbol for 'un-American' ("unamerican").[4]
According to the principle of acrophony, the letter A originated from the Proto-Sinatic alphabet as a symbol representing the head of an ox or cow (aleph), its orientation and original meaning having been lost over time. The turned A symbol restores the letter to a more easily recognizable logographic representation of an ox's head.[5]
U+1D44 ᵄ MODIFIER LETTER SMALL TURNED A is used in the Uralic Phonetic Alphabet.[6]
Encodings
| Preview | Ɐ | ɐ | ∀ | |||
|---|---|---|---|---|---|---|
| Unicode name | LATIN CAPITAL LETTER TURNED A | LATIN SMALL LETTER TURNED A | FOR ALL | |||
| Encodings | decimal | hex | dec | hex | dec | hex |
| Unicode | 11375 | U+2C6F | 592 | U+0250 | 8704 | U+2200 |
| UTF-8 | 226 177 175 | E2 B1 AF | 201 144 | C9 90 | 226 136 128 | E2 88 80 |
| Numeric character reference | Ɐ |
Ɐ |
ɐ |
ɐ |
∀ |
∀ |
| Named character reference | ∀, ∀ | |||||
| Symbol font | 34 | 22 | ||||
| TeX | \forall | |||||
See also
- List of logic symbols
- List of mathematical symbols
- Transformation of text
- Rotated letter
References
- ISBN 9783110153668.
- ^ Miller, Jeff. "Earliest Uses of Symbols of Set Theory and Logic". Earliest Uses of Various Mathematical Symbols.
- ^ Michael Everson, Proposal to add Latin letters and a Greek symbol to the UCS, ISO/IEC JTC1/SC2/WG2 N3122 L2/06-266 (2006)
- ^ Page 320 in Randall Dipert, "Peirce's deductive logic". In Cheryl Misak, ed. The Cambridge Companion to Peirce. 2004
- ISBN 9780044000211.
- ^ Everson, Michael; et al. (2002-03-20). "L2/02-141: Uralic Phonetic Alphabet characters for the UCS" (PDF).
Common logical symbols | |
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