Mathematical symbols commonly used in probability, statistics, linear algebra, and calculus, along with their descriptions:
| Symbol | Description |
|---|---|
| 𝔼 | Expectation (from probability/statistics) |
| σ | Standard deviation (from probability/statistics) |
| ‖x‖ | Vector norm (from linear algebra and multivariable calculus) |
| +C | Arbitrary constant of integration (from calculus) |
| μ | Mean or average (from probability/statistics) |
| ∇ | Nabla or del operator (gradient, from vector calculus) |
| ∫ | Integral sign (from calculus) |
| ∑ | Summation sign (used to denote the sum of a sequence of numbers) |
| ⟨x, y⟩ | Inner product or dot product (from linear algebra) |
| 𝑃(A) | Probability of event A (from probability) |
| ∂ | Partial derivative (from multivariable calculus) |
| 𝜆 | Lambda, often used for eigenvalues or rate parameters in Poisson distributions (from linear algebra and probability/statistics) |
| 𝑅² | Coefficient of determination (from statistics) |
| 𝛼 | Alpha, significance level in hypothesis testing (from statistics) |
| ∈ | Element of (used to denote membership in a set) |
| ∅ | Empty set (a set with no elements) |
| ⊥ | Perpendicular or orthogonal (from geometry and linear algebra) |
| ⊕ | Direct sum (used in linear algebra and group theory) |
| ⋂ | Intersection of sets (from set theory) |
| ⋃ | Union of sets (from set theory) |