Mathematica cannot simplify a product of UnitStep functions

*To*: mathgroup at smc.vnet.net*Subject*: [mg55118] Mathematica cannot simplify a product of UnitStep functions*From*: Alain Cochard <alain at geophysik.uni-muenchen.de>*Date*: Sun, 13 Mar 2005 04:57:37 -0500 (EST)*Reply-to*: alain at geophysik.uni-muenchen.de*Sender*: owner-wri-mathgroup at wolfram.com

Consider the following: Mathematica 4.0 for Linux Copyright 1988-1999 Wolfram Research, Inc. -- Motif graphics initialized -- In[1]:= e1=UnitStep[x-y]; e2=UnitStep[x-z]; In[2]:= FullSimplify[{e1,e2,e1*e2},x<y<z] Out[2]= {0, 0, UnitStep[x - y, x - z]} I find it strange that it cannot simplify the product to 0. Is there something mathematically profound here, implying that the true result is indeed not 0?? (At least I hope it's not something trivial!) Assuming the answer is no, is there a smarter/more elegant way to perform the simplification than the workaround I found, which is to simplify each term and multiply them. Thanks in advance. AC

**Follow-Ups**:**Re: Mathematica cannot simplify a product of UnitStep functions***From:*yehuda ben-shimol <bsyehuda@gmail.com>