## Quick Reference

**Symbol****Reference**

∞ infinity

! see factorial

′ For a function f, f′(*x*) is the derivative of f(*x*) with respect to *x*

′ For a set, see complementary event

′ For a matrix, see matrix

(*a*, *b*) an open interval, i.e. the set of real numbers between *a* and *b*: *a*<*x*<*b*

ℝ the set of all real numbers

ℝ*n* the set of all row vectors, or column vectors, with *n* real elements

∪ union

∩ intersection

≈ approximately equal to

< less than

≤ less than or equal to

> greater than

≥ greater than or equal to

→ tends to, e.g. *n* → ∞

|*x*| absolute value of *x*

*a**b**a* raised to the power *b*

*a* ½ √*a*, the (positive) square root of *a*

B beta function, see beta function

*∂**y*/*∂**x* partial derivative of *y* with respect to *x*. See Hessian matrix

Max {*x*1, *x*2,…, *x**n*} the greatest of {*x*1, *x*2,…, *x**n*}

Min {*x*1, *x*2,…, *x**n*} the least of {*x*1, *x*2,…, *x**n*}

Sign(*x*) the sign of *x*, i.e.

**X** a matrix

**x** a vector

{*r**j*} the set *r*1, *r*2,…

Binomial coefficient

Σ sum of terms

Π product of terms

From *A Dictionary of Statistics* in Oxford Reference.

*Subjects:*
Probability and Statistics.

## Related content in Oxford Index

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.