Name: Ben-Wei Zhang Date: 08/11/06-04:54:00 PM Z


Hi Michael,

If you do

DiracReduce[DIFF1]

you will find it gives zero just as DIFF2=0

Benwei

On 8/11/06, Michael <[noreply_at_HIDDEN-E-MAIL]> wrote:
>
> Hi!
>
> When I use DiracReduce I do find different results in the end depending on
> the order I use DiracReduce on substructures of the whole expression. Looks
> like this (of course normally bigger structures):
>
> T1 = (-MT[a, b] + GA[a, b]).(-MT[c, d] + GA[c, d])
> T2 = (-MT[a, b] + GA[a, b]);
> T3 = (-MT[c, d] + GA[c, d]);
> DR1 = DiracReduce[T1]
> DR2 = DiracReduce[DiracReduce[T2].DiracReduce[T3]]
> DR3 = DiracReduce[Calc[DiracReduce[T2].DiracReduce[T3]]]
> DIFF1 = Calc[DR2 - DR3]
> DIFF2 = Calc[DR1 - DR3]
>
> DIFF2 is 0. DIFF1 not. (Introducing Calc in DR3 to make DIFF2 zero does
> not work generally)
> Am I doing something wrong?
>
> Thanks very much for all your work.
> Regards
> Michael
>
>