In the mathematical field of algebraic topology, a commutative ring spectrum, roughly equivalent to a
The category of commutative ring spectra over the field
Example: The Witten genus may be realized as a morphism of commutative ring spectra MString →tmf.
See also: simplicial commutative ring, highly structured ring spectrum and derived scheme.
Terminology
Almost all reasonable categories of commutative ring spectra can be shown to be Quillen equivalent to each other. Thus, from the point view of the stable homotopy theory, the term "commutative ring spectrum" may be used as a synonymous to an