I have a very long result in my computation where every term carries two delta functions, e.g. a term in the result is of the following form
All the terms are supposed to be integrated over
om3 but the sum in the first delta functions differs for different terms (instead of
om1+om2 it might be
g are some arbitrary functions whose further specifications are unimportant (they differ for different terms).
Performing the integration term by term takes a very long time. I just wonder if I can use
ReplaceAll to "manually" contract the Delta functions. That is, the upper example would just leave me with the term
f[om]*g[-om1] which finally needs to be integrated over
I struggle a little bit, because I don't know how to define a general replacement rule to contract the Delta functions for the different variants and eventually get rid of them in the replacement.