Homotopy actions, cyclic maps and their duals

Martin Arkowitz ; Gregory Lupton

Homology, homotopy, and applications, Tome 7 (2005) no. 1, pp. 169-184.

Résumé

An action of $A$ on $X$ is a map $F \colon A \times X \to X$ such that $F\vert_X = \mathrm{id} \colon X \to X$. The restriction $F\vert_A \colon A \to X$ of an action is called a cyclic map. Special cases of these notions include group actions and the Gottlieb groups of a space, each of which has been studied extensively. We prove some general results about actions and their Eckmann-Hilton duals. For instance, we classify the actions on an $H$-space that are compatible with the $H$-structure. As a corollary, we prove that if any two actions $F$ and $F'$ of $A$ on $X$ have cyclic maps $f$ and $f'$ with $\Omega f = \Omega f'$, then $\Omega F$ and $\Omega F'$ give the same action of $\Omega A$ on $\Omega X$. We introduce a new notion of the category of a map $g$ and prove that $g$ is cocyclic if and only if the category is less than or equal to $1$. From this we conclude that if $g$ is cocyclic, then the Berstein-Ganea category of $g$ is $\le 1$. We also briefly discuss the relationship between a map being cyclic and its cocategory being $\le 1$.

Détail

DOI : 10.4310/HHA.2005.v7.n1.a9

Classification : 55M30, 55P30, 55Q05
Keywords: action, cyclic map, category of a map, coaction, cocyclic map, cocategory of a map