In number theory, σ is included in various divisor functions, especially the sigma function or sum-of-divisors function. In applied mathematics, σ (T) denotes the spectrum of a linear map T.

Learn about the Greek letter Sigma (σ), its pronunciation, usage examples, and common applications in mathematics, science, and engineering.

I love Sigma, it is fun to use, and can do many clever things. So means to sum things up ... Sum whatever is after the Sigma:

May 18, 2025 · Letter σ • (s) (lowercase, uppercase Σ) Lower-case sigma (σίγμα), the 18th letter of the ancient Greek alphabet. It represented the voiceless alveolar fricative /s/. It is preceded …

The small letter sigma (σ) is used to represent standard deviation in math and statistics. It is also used to show syllable in linguistic, a shielding constant in chemistry and sum of divisors in math.

In number theory, σ is included in various divisor functions, especially the sigma function or sum-of-divisors function. In applied mathematics, σ (T) denotes the spectrum of a linear map T.

Sigma is unique among Greek letters for having three different forms: uppercase Σ, lowercase σ (used in the middle or beginning of words), and final form ς (used only at the end of words).