Graph theory

A branch of mathematics that studies the relationships and connections between objects in an abstract sense. Graphs consist of nodes connected by edges, and can model a wide range of structures: roads connecting at intersections, books arranged by subject in a library, or web pages linked by hyperlinks. The structure of the World Wide Web is a graph, and understanding graph properties helps explain accessibility challenges. For example, the connectedness of a website — whether all pages can be reached from the home page — is a graph property. Orphaned pages, circular navigation traps, and deeply nested content are all graph-level problems that affect users of assistive technology disproportionately because they typically navigate sequentially rather than spatially.