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# Homology, Homotopy and Applications

## Volume 3 (2001)

### Number 1

### Chain functors with isomorphic homology

Pages: 37 – 53

DOI: http://dx.doi.org/10.4310/HHA.2001.v3.n1.a2

#### Author

#### Abstract

Every chain functor ${\bf K}_{*}$ determines a homology theory on a given category of topological spaces resp. of spectra $H_{*}(\bf K_{*})(\cdot)$ cf. \S 4. If $\bf K_{*}$, ${\bf L}_{*}$ are chain functors such that $H_{*}({\bf K}_{*})(\cdot) \approx H_{*}({\bf L}_{*})(\cdot)$ then there exists a third chain functor ${\bf C}_{*}$ and transformations of chain functors ${}^{K}\gamma :{\bf K}_{*} \longrightarrow {\bf C}_{*}$, ${}^{L}\gamma:\ {\bf L}_{*} \longrightarrow {\bf C}_{*}$ inducing isomorphisms of the associated homology theories (theorem 1.1.). Moreover the distinction between regular and irregular chain functors is introduced.

#### 2010 Mathematics Subject Classification

55N20