Filaments from the galaxy distribution and from the velocity field in
  the local universe
  The cosmic web that characterizes the large-scale structure of the Universe
can be quantified by a variety of methods. For example, large redshift surveys
can be used in combination with point process algorithms to extract long
curvilinear filaments in the galaxy distribution. Alternatively, given a full
3D reconstruction of the velocity field, kinematic techniques can be used to
decompose the web into voids, sheets, filaments and knots. In this paper we
look at how two such algorithms - the Bisous model and the velocity shear web -
compare with each other in the local Universe (within 100 Mpc), finding good
agreement. This is both remarkable and comforting, given that the two methods
are radically different in ideology and applied to completely independent and
different data sets. Unsurprisingly, the methods are in better agreement when
applied to unbiased and complete data sets, like cosmological simulations, than
when applied to observational samples. We conclude that more observational data
is needed to improve on these methods, but that both methods are most likely
properly tracing the underlying distribution of matter in the Universe.
