Chiral fermions on the lattice: A Flatlander's ascent into five dimensions

We briefly review how exact chiral symmetry is realised on the lattice, in particular how chiral fermions are implemented in the context of lattice QCD. We discuss how the theory can be formulated in five dimensions and this provides a theoretical framework within which one can compare algorithmic alternatives for simulating light chiral fermions in QCD on the lattice.