  The dual to a tetrahedron consists of a single vertex at which four edges and
six faces are incident. Along each edge, three faces converge. A 2-foam is a
compact topological space such that each point has a neighborhood homeomorphic
to a neighborhood of that complex. Knotted foams in 4-dimensional space are to
knotted surfaces, as knotted trivalent graphs are to classical knots. The
diagram of a knotted foam consists of a generic projection into 4-space with
crossing information indicated via a broken surface. In this paper, a finite
set of moves to foams are presented that are analogous to the Reidemeister-type
moves for knotted graphs. These moves include the Roseman moves for knotted
surfaces. Given a pair of diagrams of isotopic knotted foams there is a finite
sequence of moves taken from this set that, when applied to one diagram
sequentially, produces the other diagram.
