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The capital Greek sigma, used to indicate a sum over a series.
Also known as: Sigma notation, Sum symbol, Capital sigma
Sigma notation compresses a long sum into one expression, with limits above and below showing where the sum starts and stops.
Indicates the sum of a sequence of terms, with the index and its limits written below and above the sign.
Contexts: Mathematics
Is the capital Greek letter sigma, chosen for 'sum'; the summation operator is a distinct character from the letter in Unicode.
U+2211 N-ARY SUMMATION is the operator; U+03A3 GREEK CAPITAL LETTER SIGMA is the letter. They look alike and are not interchangeable.
Contexts: Mathematics
An angular figure of two diagonal strokes meeting a vertical spine, like a pointed E.
This sign is the capital Greek letter sigma. The lowercase letter names a quantity — standard deviation, stress — while this capital instructs an operation, and readers routinely take the two for one symbol.
Discrete sums and continuous integrals are the paired operations of calculus.