Sum

*To*: mathgroup at smc.vnet.net*Subject*: [mg84202] Sum*From*: Benoît Frénay <benoit.frenay at uclouvain.be>*Date*: Thu, 13 Dec 2007 07:05:10 -0500 (EST)

Hello, If I feed Mathematica with the following expression *>>> Sum[i == j, {i, 1, n}, {j, 1, n}] *then nothing happens : it is not able to evaluate the expression. But if I set *>>> **n = 100* and then feed *>>> **Sum[i == j, {i, 1, n}, {j, 1, n}] *again, then I receive *>>> **9900 False + 100 True* Is it possible to obtain *>>> **False (-1 + n) n + n^2 True* when I feed the above sum? Thanks, Benoît Frénay