<p>Assuming network access is sporadic with no central server, what would be the best way to use git to keep three or more branches in sync? Is there a way to extract just my deltas, email those, and merge them on the other end?</p>

See the main pages for
```
git-format-patch
```
and
```
git-am
```
. This is one of the ways the system was originally designed to work with.