  In a recent paper, with Drago and Pinamonti we have introduced a
Wetterich-type flow equation for scalar fields on Lorentzian manifolds, using
the algebraic approach to perturbative QFT. The equation governs the flow of
the effective average action, under changes of a mass parameter k. Here we
introduce an analogous flow equation for gauge theories, with the aid of the
Batalin-Vilkovisky (BV) formalism. We also show that the corresponding
effective average action satisfies a Slavnov-Taylor identity in Zinn-Justin
form. We interpret the equation as a cohomological constraint on the functional
form of the effective average action, and we show that it is consistent with
the flow.
