7. A1 -homotopy theory 7.1. Closed model categories. We begin with
... which is the identity on objects and whose set of morphisms from X to Y equals the set of homotopy classes of morphisms from some fibrant/cofibrant replacement of X to some fibrant/cofibrant replacement of Y : HomHo(C) (X, Y ) = π(RQX, RQY ). If F : C → D if a functor with the property that F sends ...
... which is the identity on objects and whose set of morphisms from X to Y equals the set of homotopy classes of morphisms from some fibrant/cofibrant replacement of X to some fibrant/cofibrant replacement of Y : HomHo(C) (X, Y ) = π(RQX, RQY ). If F : C → D if a functor with the property that F sends ...