connective spectrum

A connective spectrum is a connective object in the stable -category of spectra, hence a spectrum whose homotopy groups in all negative degrees are trivial: . These are equivalently: Connective spectra form a sub-(∞,1)-category of spectra There are objects in Spectra, though, that do not come from “naively” delooping a topological space infinitely many times. These are the non-connective spectra. For general spectra there is a notion of homotopy groups of negative degree. The connective ones...