AugmentedTopologyMarker is an option for
FCLoopTensorReduce, FCLoopAugmentTopology and
other functions. It marks topologies (written as GLIs denoting
denominators only) that need to be augmented with propagators containing
the given external momenta. This case usually occurs when doing a tensor
reduction with zero Gram determinant and light-like external momenta, so
that an auxiliary vector must be added to the basis.
Overview, FCLoopTensorReduce, FCLoopAugmentTopology.