Re: different output!!

*To*: mathgroup at smc.vnet.net*Subject*: [mg97022] Re: different output!!*From*: "Sjoerd C. de Vries" <sjoerd.c.devries at gmail.com>*Date*: Mon, 2 Mar 2009 05:22:58 -0500 (EST)*References*: <godm3n$46c$1@smc.vnet.net>

It seems correct to me. Please note that Mod[x,5] is not necessarily integer and therefore not countable if x is a real whereas it is countable when x is an integer. Reduce does a fine job here. Cheers -- Sjoerd On Mar 1, 11:56 am, olfa <olfa.mra... at yahoo.fr> wrote: > Hi Mathematica community, > Why output2 (with integers as domain) is different from output1 (with > reals as domain) ?!! I think it should be the same thing. > > input1:Reduce[{Mod[x, 5] == Mod[xP, 5], 0 <= xP < 5}, {xP}, Reals, > Backsubstitution -> True] > > output1: 0 <= Mod[x, 5] < 5 && xP == Mod[x, 5] > > input2:Reduce[{Mod[x, 5] == Mod[xP, 5], 0 <= xP < 5}, {xP}, Integer= s, > Backsubstitution -> True] > > output2: (Mod[x, 5] == 0 && xP == 0) || (Mod[x, 5] == 1 && > xP == 1) || (Mod[x, 5] == 2 && xP == 2) || (Mod[x, 5] = == 3 && > xP == 3) || (Mod[x, 5] == 4 && xP == > 4)