  We explain how the 't Hooft expansion of correlators of half-BPS operators
can be resummed in a large-charge limit in N=4 super Yang-Mills theory. The
full correlator in the limit is given by a non-trivial function of two
variables: One variable is the charge of the BPS operators divided by the
square root of the number Nc of colors; the other variable is the octagon that
contains all the 't Hooft coupling and spacetime dependence. At each genus g in
the large Nc expansion, this function is a polynomial of degree 2g+2 in the
octagon. We find several dual matrix model representations of the correlators
in the large-charge limit. Amusingly, the number of colors in these matrix
models is formally taken to zero in the relevant limit.
