Full paper in PDF:
$%M. R. Casali, Two-fold branched coverings of
have type six,
Rev. Mat. Univ. Complut. Madrid 5 (1992), no. 2, 3, 235–254.%$
Two-Fold Branched Coverings of
Have
Type Six
In this work, we prove that every closed, orientable 3-manifold
which is a
two-fold covering of
branched over a link, has type six. This implies that
is the quotient of the universal pseudocomplex
by the action of
a finite index subgroup of a Fuchsian group with presentation
Moreover, the same result is proved to be true in case
being an unbranched
covering of a two-fold branched covering of
.
1991 Mathematics Subject Classification: 57Q15, 57M12; 05C10, 57M25.