Symbolic collection using Deep Thought

Abstract: We describe the "Deep Thought" algorithm, which can, among other things, take a commutator presentation for a finitely generated torsion-free nilpotent group G, and produce explicit polynomials for the multiplication of elements of G. These polynomials were first shown to exist by Philip Hall, and allow for "symbolic collection" in finitely generated nilpotent groups. We discuss various practical issues in calculations in such groups, including the construction of a hybrid collector, making use of both the polynomials and ordinary collection from the left.