The tropical vertex is an incarnation of mirror symmetry found by Gross,
Pandharipande and Siebert. It can be applied to m-Kronecker quivers K(m)
(together with a result of Reineke) to compute the Euler characteristics of the
moduli spaces of their (framed) representations in terms of Gromov-Witten
invariants (as shown by Gross and Pandharipande). In this paper, we study a
possible geometric picture behind this correspondence, in particular
constructing rational tropical curves from subquivers of the universal covering
quiver of K(m). Additional motivation comes from the physical interpretation of
m-Kronecker quivers in the context of quiver quantum mechanics (especially work
of F. Denef).Comment: 33 pages, 8 figures. Completely revised, published versio