In this paper we show that periodic Takahashi 3-manifolds are cyclic
coverings of the connected sum of two lens spaces (possibly cyclic coverings of
the 3-sphere), branched over knots. When the base space is a 3-sphere, we prove
that the associated branching set is a two-bridge knot of genus one, and we
determine its type. Moreover, a geometric cyclic presentation for the
fundamental groups of these manifolds is obtained in several interesting cases,
including the ones corresponding to the branched cyclic coverings of the
3-sphere.Comment: 12 pages, 5 figures. To appear in Tsukuba Journal of Mathematic
