  The present article completes an earlier publication, which was the
culmination of a series of papers dedicated to the study of the planar graphs
of the scalar phi^3 theory on a light cone world sheet. In the earlier work, a
field theory on a continuous world sheet that reproduces these planar graphs
was constructed, and the mean field approximation was applied to it. This led
to the formation of a soliton, and the fluctuations around the soliton were
identified with stringy excitations. We point out, however, that in this
earlier work, a complete treatment of the ground state of the model was
missing. This was due to an unnecessary decompactification of the world sheet;
by keeping it compactified, we show that, in addition to a trivial ground
state, there is also a non-trivial one. We investigate fluctuations around the
non-trivial ground state in the limit of a densely populated world sheet, and
show string formation in this limit. We also show that this limit can be
systematically studied by means of an expansion in terms of a conveniently
defined coupling constant.
