Stable homotopy category
= Stable homotopy category
{title2=$[D,E]_{\mathrm{st}}$}
{wiki}
The <stable homotopy category> is obtained from <topological spectra> by inverting <stable equivalences of spectra>. Its morphisms are abelian groups; for a cellular source and fibrant target they are <spectrum homotopy> classes of point-set <maps of topological spectra>.