Σ

See also: σ, ς, ∑, ⵉ, Ʃ, σ., and σ'

Σ U+03A3, Σ GREEK CAPITAL LETTER SIGMA [unassigned: U+03A2] ← Ρ [U+03A1] Greek and Coptic Τ → [U+03A4]

Translingual

Symbol

Σ

1. (mathematics) Σ. Sum over a set of like terms:

   $\sum _{n=1}^{2}n^{2}=1^{2}+2^{2}=5$

2. (topology) suspension or reduced suspension
3. (mathematics) A class (in the arithmetical hierarchy) of formulae whose outermost unbounded quantifiers are existential quantifiers

Usage notes

(mathematics): Though there exists a distinct symbol (∑) for the purpose of the mathematical summation, the upper case sigma here is often used for convenience.

Coordinate terms

• (classification of formulae): Π, Δ

See also

• Σ on Wikipedia.Wikipedia

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Greek

Letter

Σ • (S) (uppercase, lowercase σ)

1. The upper case letter sigma (σίγμα), the 18th letter of the modern Greek alphabet.

Numeral

Σ • (S)

1. The number 200 in Greek numerals.

,Σ

1. The number 200,000 in Greek numerals.

See also

see: Appendix:Greek alphabet