Large - N Limit and Contact Terms in Unbroken Ym

I characterize the structure of the master field for F 0 z ¯ z in SU(∞)-Y M 4 on a product of two Riemann surfaces Z × W in the gauge F ch z ¯ z = 0 as the sum of a 'bulk' constant term and of delta-like 'contact' terms. The contact terms may occur because the localization of the functional integral at N = ∞ on a master orbit of a constant connection under the action of singular gauge transformations is still compatible with the large-N factor-ization and translational invariance. In addition I argue that if the gauge group is unbroken and there is a mass gap, that is if the theory confines, the functional measure at N = ∞, in the gauge F ch z ¯ z = 0, must be localized on the moduli space of flat connections