Communications of the Korean Mathematical Society (대한수학회논문집)
- Volume 11 Issue 4
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- Pages.1077-1085
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- 1996
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- 1225-1763(pISSN)
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- 2234-3024(eISSN)
APPROXIMATE FIBRATIONS AND NON-APPROXIMATE FIBRATIONS IN PL CATEGORY
Abstract
This paper provides examples which can not be approximate fibrations and shows that if $N^n$ is a closed aspherical manifold, $\pi_1(N)$ is hyperhophian, normally cohophian, and $\pi_1(N)$ has no nontrivial Abelian normal subgroup, then the product of $N^n$ and a sphre $S^m$ satisfies the property that all PL maps from an orientable manifold M to a polyhedron B for which each point preimage is homotopy equivalent to $N^n \times S^m$ necessarily are approximate fibrations.