  In some processes at the LHC, theoretical precisions of 1 percent are
desired. With an eye toward such precisions, we introduce the theory of the
simultaneous YFS resummation of QED and QCD to compute the size of the expected
resummed soft radiative threshold effects in precision studies of heavy
particle production at the LHC. Our results, that the soft QED threshold
effects are at the level of 0.3 percent whereas the soft QCD threshold effects
enter at the level of 20 percent, show that both must be controlled to be on
the conservative side to achieve such precision goals.
