Let
G be a finite group and let
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0001870815300062&_mathId=si1.gif&_user=111111111&_pii=S0001870815300062&_rdoc=1&_issn=00018708&md5=aabcedaca6a529b65644a7086d88c821" title="Click to view the MathML source">Fclass="mathContainer hidden">class="mathCode"> be a family of subgroups of
G. We introduce a
class of
G -equivariant spectra that we call
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0001870815300062&_mathId=si1.gif&_user=111111111&_pii=S0001870815300062&_rdoc=1&_issn=00018708&md5=aabcedaca6a529b65644a7086d88c821" title="Click to view the MathML source">Fclass="mathContainer hidden">class="mathCode">-nilpotent . This definition fits into the general theory of torsion, complete, and nilpotent objects in a symmetric monoidal stable ∞-category, with which we begin. We then develop some of the basic properties of
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0001870815300062&_mathId=si1.gif&_user=111111111&_pii=S0001870815300062&_rdoc=1&_issn=00018708&md5=aabcedaca6a529b65644a7086d88c821" title="Click to view the MathML source">Fclass="mathContainer hidden">class="mathCode">-nilpotent
G-spectra, which are explored further in the sequel to this paper.
In the rest of the paper, we prove several general structure theorems for ∞-categories of module spectra over objects such as equivariant real and complex K-theory and Borel-equivariant MU. Using these structure theorems and a technique with the flag variety dating back to Quillen, we then show that large classes of equivariant cohomology theories for which a type of complex-orientability holds are nilpotent for the family of abelian subgroups. In particular, we prove that equivariant real and complex K-theory, as well as the Borel-equivariant versions of complex-oriented theories, have this property.