These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 0.99 s (backtrack: 0/20).

[ebuild  N     ] sci-libs/cddlib-094n::gentoo  USE="-doc -examples -static-libs -tools" 1349 KiB
[ebuild  N     ] sci-mathematics/topcom-0.17.8-r3::gentoo  USE="-examples" 8803 KiB

Total: 2 packages (2 new), Size of downloads: 10152 KiB