  We employ a solution of the Yang-Baxter equation to construct invariants for
knot-like objects. Specifically, we consider a Yang-Baxter state model for the
sl(n) polynomial of classical links and extend it to oriented singular links
and balanced oriented 4-valent knotted graphs with rigid vertices. We also
define a representation of the singular braid monoid into a matrix algebra, and
seek conditions for extending further the invariant to contain topological
knotted graphs. In addition, we show that the resulting Yang-Baxter-type
invariant for singular links yields a version of the Murakami-Ohtsuki-Yamada
state model for the sl(n) polynomial for classical links.
