In mathematics, the Peterson–Stein formula, introduced by Franklin P. Peterson and Norman Stein (1960), describes the Spanier–Whitehead dual of a secondary cohomology operation.
References Peterson, F. P.; Stein, N. (1960), "The dual of a secondary cohomology operation", Illinois Journal of Mathematics, 4 (3): 397–404, doi:10.1215/ijm/1255456056, ISSN 0019-2082, MR 0151967