Hopf invariants, Toda brackets and the reduced diagonal map

Abstract

That there is a close connection between crude (or suspended) Hopf invariants and the reduced diagonal map has long been known. In this paper we build on a classical result of Boardman and Steer (1967) to explore some further relationships in terms of conic structures. In a related result we show that certain Toda brackets contain crude Hopf invariants as elements. In particular, using this latter observation, detection of crude Hopf invariants can be carried out.