`r1` or `r2` but not from both.
Two other shorthands for naming a set that is formed by a commit
-and its parent commits exists. `r1{caret}@` notation means all
+and its parent commits exist. The `r1{caret}@` notation means all
parents of `r1`. `r1{caret}!` includes commit `r1` but excludes
-its all parents.
+all of its parents.
Here are a handful of examples: