  Applications, such as military and disaster response, can benefit from
robotic collectives' ability to perform multiple cooperative tasks (e.g.,
surveillance, damage assessments) efficiently across a large spatial area.
Coalition formation algorithms can potentially facilitate collective robots'
assignment to appropriate task teams; however, most coalition formation
algorithms were designed for smaller multiple robot systems (i.e., 2-50
robots). Collectives' scale and domain-relevant constraints (i.e.,
distribution, near real-time, minimal communication) make coalition formation
more challenging. This manuscript identifies the challenges inherent to
designing coalition formation algorithms for very large collectives (e.g., 1000
robots). A survey of multiple robot coalition formation algorithms finds that
most are unable to transfer directly to collectives, due to the identified
system differences; however, auctions and hedonic games may be the most
transferable. A simulation-based evaluation of three auction and hedonic game
algorithms, applied to homogeneous and heterogeneous collectives, demonstrates
that there are collective compositions for which no existing algorithm is
viable; however, the experimental results and literature survey suggest paths
forward.
