Model -categories III: the fundamental theorem
arXiv:1510.04777
Abstract
We prove that a model structure on a relative -category gives an efficient and computable way of accessing the hom-spaces in the localization. More precisely, we show that when the source is *cofibrant* and the target is *fibrant*, then this hom-space is a "quotient" of the hom-space by either of a *left homotopy relation* or a *right homotopy relation*.