Re: question (for Mathematica 6!)

*To*: mathgroup at smc.vnet.net*Subject*: [mg75555] Re: question (for Mathematica 6!)*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Sat, 5 May 2007 05:58:12 -0400 (EDT)*References*: <f1ept5$4n1$1@smc.vnet.net>

Hi, {HeavisideTheta[#], UnitStep[#]} & /@ {-0.1, 0, 0.1} gives {{0, 0}, {HeavisideTheta[0], 1}, {1, 1}} the Heaviside Theta function is a distribution, i.e. it only exist/is defined in expressions like Integrate[HeavisideTheta[x]*f[x],{x,-a,a}] and it has no defined value at 0 (look for DiracDelta[] that is also a distriution). The UnitStep[] function is defined everywhere on the axis and you don't need an integral to define it Regards Jens dimitris wrote: > I don't have a copy of Mathematica 6 but having spent much time > reading the online documentation (not only because of curiosity!) I > have one question... > > Can somebody explain me the introduction of the HeavisideTheta > function > > http://reference.wolfram.com/mathematica/ref/HeavisideTheta.html > > in version 6? > > Note that the UnitStep function is still here > > http://reference.wolfram.com/mathematica/ref/UnitStep.html > > Dimitris > >