Stigma (letter) sigma form ς never occurs inside a word and is never used as a numeral either. Uppercase forms of stigma as a numeral (Ϛ) are rare in practice; when they occur, they can often be confused with uppercase forms of another numeral symbol, koppa (Ϟϟ), which stands for 90. Stigma is encoded in Unicode as "Greek letter stigma" U+03DA (Ϛ) and "Greek small letter stigma" U+03DB (ϛ). Stigma (letter) Stigma (ϛ) is a ligature of the Greek letters sigma (Σ) and tau (Τ), which was used in writing Greek between the Middle Ages and the 19th century. It is also
Greek Braille ά, Ά, αί. It's not used for diaeresis; ϊ is just . Digits are the same as in English Braille. Arithmetical symbols are: International letter assignments differ somewhat from those above. In Modern Greek Braille, for example, the letter omega (ω) is written the same as Latin "j", whereas in English or French braille texts it is written as a "w", which it resembles in print. Similarly, Modern Greek upsilon is written as Latin "y", but in international Greek it's written as "u", and the letter eta is inverted. This alphabet is used, for example, in mathematical notation in an