Unitize[x] gives 0 when x is zero, and 1 when x has any other numerical value.

MathLink is a protocol for exchanging symbolic expressions. The Mathematica-level MathLink functions can be used with any MathLink-enabled external program, including ...

Pattern matching makes possible some of the most succinct and elegant programs in the Mathematica language—immediately compressing large numbers of conditional cases into ...

Mathematica handles many different kinds of things: mathematical formulas, lists, and graphics, to name a few. Although they often look very different, Mathematica represents ...

Limit[expr, x -> x_0] finds the limiting value of expr when x approaches x_0.

AiryBi[z] gives the Airy function Bi(z).

DiscreteIndicator[x, x_1, {u_1, u_2, ...}] yields the discrete indicator function, equal to 1 if x = x_1 and 0 if x = u_i for any i.

Install["name"] starts a MathLink-compatible external program and installs Mathematica definitions to call functions in it.

InverseZTransform[expr, z, n] gives the inverse Z transform of expr. InverseZTransform[expr, {z_1, z_2, ...}, {n_1, n_2, ...}] gives the multiple inverse Z transform of expr.

Normal[expr] converts expr to a normal expression, from a variety of special forms.