Classification schemes typically used in libraries are strictly hierarchical, which can be useful for organization of resources, but does not reflect the more general structure of the universe of knowledge. Epistemologically, knowledge has other types of relationships between resources (e.g. ontologies reflect this well). Graph theory in the computer science field provides compelling transformations from existing classification schemes to novel representations. Tries, the structure that decimal schemes use, when transformed to more general structures, solve a number of issues, both epistemological and logistical (logistical issues being shelving, discoverability, and other physical library considerations).