• To: mathgroup at smc.vnet.net
• From: olfa <olfa.mraihi at yahoo.fr>
• Date: Thu, 16 Apr 2009 04:15:57 -0400 (EDT)

```Hi Mathematica community,
I have to solve this system:
Reduce[{Element[{i, j}, Integers], i <= iP, j >= jP,
1*j + 1*i == 1*jP + 1*iP,
Reduce[{Element[{N, iP}, Integers], Not[(iP < N)],
Exists[{iPP}, (iPP < N) && iP == iPP + 1]}]}, {iP, jP},
Backsubstitution -> True]

the output should be:( i | j | N | iP) are Integers && i <= N && iP ==
N &&
jP == i + j - N
but mathematica gave me this output:
(C[1] | C[2] | C[3] | C[4]) are Integers && C[1] >= 0 &&
C[2] >= 0 && C[3] >= 0 && C[4] >= 0 && i == C[1] - C[2] - C[3] &&
iP == C[1] - C[2] + C[4] && N == C[1] - C[2] + C[4] &&
jP == j - C[3] - C[4]

which is not understandable at all! and I dont want the output to be
like that.

I have observed that when I remove i from Element[{i, j}, Integers]
mathematica give me the output I want and which is :iP == N &&  jP ==
i + j - N

So how can I have this same output without removing i from Element[{i,
j}, Integers]?

Thank you very much in advance.

```