Mikhail Khovanov, Columbia University, Categorifications of natural numbers, integers and fractions
SAS 1102Categorification lifts natural numbers to vector spaces and integers to complexes. Natural number n becomes a vector space of dimension n, and an integer becomes the Euler characteristic of a complex of vector spaces. A well-known example of categorification is lifting the Euler characteristic of a topological space to its homology or cohomology groups. The…