  We consider the polynuclear growth (PNG) model in 1+1 dimension with flat
initial condition and no extra constraints. Through the
Robinson-Schensted-Knuth (RSK) construction, one obtains the multilayer PNG
model, which consists of a stack of non-intersecting lines, the top one being
the PNG height. The statistics of the lines is translation invariant and at a
fixed position the lines define a point process. We prove that for large times
the edge of this point process, suitably scaled, has a limit. This limit is a
Pfaffian point process and identical to the one obtained from the edge scaling
of Gaussian orthogonal ensemble (GOE) of random matrices. Our results give
further insight to the universality structure within the KPZ class of 1+1
dimensional growth models.
