represents the unit step function, equal to 0 for and 1 for .

represents the multidimensional unit step function which is 1 only if none of the are negative.


  • Some transformations are done automatically when UnitStep appears in a product of terms.
  • UnitStep provides a convenient way to represent piecewise continuous functions.
  • UnitStep has attribute Orderless.
  • For exact numeric quantities, UnitStep internally uses numerical approximations to establish its result. This process can be affected by the setting of the global variable $MaxExtraPrecision.
  • UnitStep[] is 1.
Introduced in 1999