In mathematics, an analytical expression (or expression in analytical form) is a mathematical expression, constructed using well-known operations that lend themselves readily to calculation. As for closed-form expressions, the criteria are not precisely defined, but the class of expressions considered to be "analytical expressions" tends to be wider.
In particular, special functions such as the Bessel functions and the gamma function are usually allowed, and often so are infinite series and continued fractions. On the other hand, limits in general, and integrals in particular, are typically excluded.