In the 1998 technical note "Computing on data streams" by Monika Rauch Henzinger , Prabhakar Raghavan , Sridar Rajagopalan (found here: http://www.eecs.harvard.edu/~michaelm/E210/datastreams.pdf)
They define a directed multigraph with node set V1 union V2 union union Vk, all of whose edges are directed from a node in Vi to a node in Vi+1.
I cannot see how this allows for disconnected components? Can anyone clarify this?
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