Abstract. Emerging pervasive computing technologies present many opportunities to aid ad-hoc collocated group collaboration. To better understand ad-hoc collaboration using pervasive technologies, or Pervasive Collaboration, a design space composed of three axes (composition granularity, sharing models, and resource references) is outlined, highlighting areas that are only partially covered by existing systems. Addressing some of these gaps, Platform Composition is a technique designed to overcome the usability limitations of small mobile devices and facilitate group activities in ad-hoc environments by enabling users to run legacy applications on a collection mobile devices. The associated Composition Framework prototype demonstrates a concrete implementation that explores the applicability of existing technologies, protocols, and applications to this model. Overall, Platform Composition promises to be an effective technique for supporting collaborative work on mobile devices, without...