In this paper we describe tropical methods for implicitization of surfaces.
We construct the corresponding tropical surfaces via the theory of geometric
tropicalization due to Hacking, Keel and Tevelev, which we enrich with a
formula for computing tropical multiplicities of regular points in any
dimension. We extend previous results for tropical implicitization of generic
surfaces due to Sturmfels, Tevelev and Yu and provide methods for the
non-generic case.
The restricted Boltzmann machine is a graphical model for binary random
variables. Based on a complete bipartite graph separating hidden and observed
variables, it is the binary analog to the factor analysis model. We study this
graphical model from the perspectives of algebraic statistics and tropical
geometry, starting with the observation that its Zariski closure is a Hadamard
power of the first secant variety of the Segre variety of projective lines.