Smash product of spectra
= Smash product of spectra
{title2=$D\wedge E$}
= Smash products of spectra
{synonym}
The derived <smash product of spectra> is the symmetric monoidal product on the <stable homotopy category>. It has unit <sphere spectrum>, preserves <cofiber sequences of spectra> and <homotopy colimits of spectra> in each variable, and satisfies $\Sigma^\infty X\wedge\Sigma^\infty Y\simeq\Sigma^\infty(X\wedge Y)$.