  This is an expository article, originally written in Japanese, on a dynamical
system over a non-archimedean field. The main viewpoint is from complex and
non-archimedean potential theories. After quickly introducing the Berkovich
projective line, the dynamical moduli space as a scheme, and the various height
functions on the space of rational functions and on the dynamical moduli space,
we first survey our study of Rumely's new equivariants in non-archimedean
dynamics and then survey our complex geometric and arithmetic studies of the
dynamical moduli space from our joint works with Thomas Gauthier and Gabriel
Vigny. The latter include a precise version of McMullen's finiteness theorem on
formally exact multiplier spectra and an effective solution of Silverman's
conjecture on a comparison between the moduli height and the critical height
(qualitatively, the Silverman-Ingram theorem). The final topic is a
degeneration of complex dynamics.
