On counting ac0 circuits with negative constants

Continuing the study of the relationship between TC0, AC0 and arithmetic circuits, started by Agrawal et al. [1], we answer a few questions left open in this paper. Our main result is that the classes DiffAC0 and GapAC0 coincide, under poly-time, log-space, and log-time uniformity. From that we can derive that under logspace uniformity, the following equalities hold: etse409-01etse