Abstract
The infrared singularities of gravitational amplitudes are one-loop exact, in that higher-loop divergences are characterized by the exponential of the one-loop divergence. We show that the contributions to SU(N) gauge-theory amplitudes that are mostsubleading in the 1/N expansion are also one-loop exact, provided that the dipole conjecture holds. Possible corrections to the dipole conjecture, beginning at three loops, could violate one-loop-exactness, though would still maintain the absence of collinear divergences. We also demonstrate a relation between L-loop four-point
$ \mathcal{N}=8 $
supergravity and mostsubleading-color
$ \mathcal{N}=4 $
SYM amplitudes that holds for the two leading IR divergences,
$ \mathcal{O}\left( {{1 \left/ {{{\in^L}}} \right.}} \right) $
and
$ \mathcal{O}\left( {{1 \left/ {{{\in^{L-1 }}} \right.}} \right) $
, but breaks down at
$ \mathcal{O}\left( {{1 \left/ {{{\in^{L-2 }}} \right.}} \right) $
.