The resource space model (RSM) is a semantic data model based on orthogonal classification semantics for efficiently managing various resources in the future interconnection environment. This paper extends the RSM in theory by formalizing the resource space, investigating its characteristics from the perspective of set theory, defining the resource space schema and developing its normal forms. The topological space properties of the resource space are presented based on the definition of a distance in the space and the construction of a quotient space structure. The proposed theory ensures the RSM to correctly and efficiently specify and manage resources.