Turned A

Turned A (capital: Ɐ or Ɒ, lowercase: ɐ or ɒ, math symbol ∀) is a symbol based upon the letter A.

Lowercase ɐ (in two story form) is used in the International Phonetic Alphabet to identify the near-open central vowel. A variant, turned alpha, ɒ, is also used in the IPA as the open back rounded vowel.

It was used in the 18th century by Edward Lhuyd and William Pryce as phonetic character for the Cornish language. In their books, both Ɐ and ɐ have been used. ^[1] It was used in the 19th century by Charles Sanders Peirce as a logical symbol for 'un-American' ("unamerican").^[2]

The symbol ∀ has the same shape of a capital turned A, sans serif. It is used to represent universal quantification in predicate logic. When it appears in a formula together with a predicate variable, they are referred to as a universal quantifier. In traffic engineering it is used to represent flow, the number of units (vehicles) passing a point in a unit of time.

Encodings

Ɐ is encoded in Unicode at U+2C6F Ɐ latin capital letter turned a (HTML: Ɐ) in the block Latin Extended-C, though very few fonts support it as of 2008, and ɐ is encoded in Unicode at U+0250 ɐ latin small letter turned a (HTML: ɐ) in the block IPA Extensions.
The similar turned alphas are at U+2C70 Ɒ latin capital letter turned alpha (HTML: Ɒ capital), and at U+0252 ɒ latin small letter turned alpha (HTML: ɒ).

The mathematical symbol ∀ is encoded at U+2200 ∀ for all (HTML: ∀ ∀), in the mathematical operators and symbols in Unicode, and only in a sans-serif form.

The Symbol font includes ∀ at position 34 (which would produce the quotation mark in ASCII and Unicode).

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References

^ 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

The ISO basic Latin alphabet v t e
Aa	Bb	Cc	Dd	Ee	Ff	Gg	Hh	Ii	Jj	Kk	Ll	Mm	Nn	Oo	Pp	Qq	Rr	Ss	Tt	Uu	Vv	Ww	Xx	Yy	Zz
Letter A with diacritics
Áá	Àà	Ăă	Ắắ	Ằằ	Ẵẵ	Ẳẳ	Ââ	Ấấ	Ầầ	Ẫẫ	Ẩẩ	Ǎǎ	Åå	Ǻǻ	Ää	Ǟǟ	Ãã	Ȧȧ	Ǡǡ	Ąą	Āā	Ảả	Ȁȁ	Ȃȃ	Ạạ
Ặặ	Ậậ	Ḁḁ	Ⱥⱥ	ᶏ	Ɐɐ	Ɑɑ
Related
Derivations Diacritics History ISO/IEC 646 List of letters Numerals Palaeography Punctuation Unicode

Logic

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Common logical symbols

& ∨ ¬ ~ → ⊃ ≡ \| ∀ ∃ ⊤ ⊥ ⊢ ⊨ ∴ ∵

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Last modified on 1 March 2013, at 04:43

Turned A

Encodings

See also

References

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