• Bulletin of the Korean Mathematical Society
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• v.35 no.3
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• pp.491-501
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• 1998

If N is any cartesian product of a closed simply connected n-manifold $N_1$ and a closed aspherical m-manifold $N_2$, then N is a codimension 2 fibrator. Moreover, if N is any closed hopfian PL n-manifold with $\pi_iN=0$ for $2 {\leq} i < m$, which is a codimension 2 fibrator, and $\pi_i N$ is normally cohopfian and has no proper normal subroup isomorphic to $\pi_1 N/A$ where A is an abelian normal subgroup of $\pi_1 N$, then N is a codimension m PL fibrator.

• Bulletin of the Korean Mathematical Society
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• v.36 no.1
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• pp.79-90
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• 1999

In this paper, we show that any product of a closed orientable n-manifold $N_1$ with finite fundamental group and a closed orientable asgerical m-mainfold $N_2$ with hopfian fundamental group, where X($N_1$) and X($N_2$) are nonzero, is a condimension 2 fibrator. Moreover, if <$\pi_i(N_1)$=0 for 1$N_1\timesN_2$ is a codimension k PL fibrator.

• Communications of the Korean Mathematical Society
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• v.25 no.2
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• pp.283-289
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• 2010

Approximate fibrations provide a useful class of maps. Fibrators give instant detection of maps in this class, and PL fibrators do the same in the PL category. We show that rational homology spheres with some additional conditions are codimension-k PL fibrators and PL manifolds with trivial homology groups in some range can be codimension-k (k > 2) PL fibrators.

• Communications of the Korean Mathematical Society
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• v.22 no.2
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• pp.289-295
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• 2007

We describe some conditions under which the product of two groups with certain property is a group with the same property, and we describe some conditions under which the product of hopfian manifolds is another hopfian manifold. As applications, we find some PL fibrators among the product of fibrators.

• Journal of the Korean Mathematical Society
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• v.43 no.1
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• pp.99-109
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• 2006

Approximate fibrations form a useful class of maps. By definition fibrators provide instant detection of maps in this class, and PL fibrators do the same in the PL category. We show that every closed s-hopfian t-aspherical manifold N with sparsely Abelian, hopfian fundamental group and X(N) $\neq$ 0 is a codimension-(t + 1) PL fibrator.

• Bulletin of the Korean Mathematical Society
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• v.43 no.4
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• pp.841-846
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• 2006

Suppose that F is a closed t-aspherical PL n-manifold with finite, sparsely abelian ${\pi}_1(F)$ and A is a closed aspherical PL m-manifold with hopfian, normally cohopfian ${\pi}_1(A)$. If $X(F){\neq}0{\neq}X(A)$, then $F{\times}A$ is a codimension-(t+1) PL fibrator.

• Honam Mathematical Journal
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• v.29 no.3
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• pp.327-339
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• 2007

Approximate fibrations form a useful class of maps. By definition fibrators provide instant detection of maps in this class, and PL fibrators do the same in the PL category. We show that every closed s-hopfian t-aspherical manifold N with some algebraic conditions and X(N) $\neq$ 0 is a codimension-(2t + 2) PL fibrator.