We prove that the categorified su3 quantum link invariant is functorial with respect
to tangle cobordisms. This is in contrast to the categorified su2 theory, which was not
functorial as originally defined.
We use methods of Morrison and Nieh and Bar-Natan to construct explicit chain
maps for each variation of the third Reidemeister move. Then, to show functoriality,
we modify arguments used by Clark, Morrison and Walker to show that induced
chain maps are invariant, up to homotopy, under Carter and Saito’s movie