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1 comment on en.wikipedia.org/wiki/Sigma

Sigma - Wikipedia

#Sigma (/?s??m?/;[1] uppercase ?, lowercase ?, lowercase in word-final position ?; Greek: ?????) is the eighteenth letter of the #Greek alphabet. In the system of Greek #numerals, it has a value of 200. In general #mathematics, uppercase ? is used as an operator for #summation. In condensed matter #physics, ? denotes self-#energy.
&neo 2022-10-17 23:13:55