A brief primer on notation and relevant mathematical concepts is provided in appendix. A. It is important to clarify that in what follows, and in the field of QCT more broadly, the term "topology" is used in a looser sense (with some exceptions -see ) than in the branch of mathematics bearing the same name. We use the term in it's broader sense as pertaining to properties of a geometric object (in our case, a quantum-mechanical function) that are preserved under continuous deformations (in our case, small deformations of a molecule). In this work, the topological properties of interest will be properties of the topography of the quantum-mechanical function of interest. For example, maxima, minima and saddle points are topographical features, but their existence and connectivity are topological properties. These topological properties are insensitive to the level of theory used to describe a molecule (e.g Hartree-Fock or DFT). However, in contrast to stricter definitions of conservation in mathematics, topological properties in QCT are typically not conserved through chemical processes, such as bond breaking or formation -a fact which underpins their usefulness in identifying and classifying such phenomena.