Proof of Theorem 6.1. Let us presentthe proof of this theorem (with some omissions). We will
assume that g is a positive real number, and compute the function W
∞(g) explicitly. We follow the
paper of Brezin, Itzykson, Parisi, and Zuber “Planar diagrams”, Comm. Math. Phys. 59, p. 35-51,
1978.
The relevant matrix integral has the form