Embedding open 3-manifolds in compact 3-manifolds

Contractible Open 3-manifolds Which Non-trivially Cover Only Non-compact 3-manifolds

Cohomology Determinants of Compact 3–manifolds

We give definitions of cohomology determinants for compact, connected, orientable 3–manifolds. We also give formulae relating cohomology determinants before and after gluing a solid torus along a torus boundary component. Cohomology determinants are related to Turaev torsion, though the author hopes that they have other uses as well.

Normal Cr Structures on Compact 3-manifolds

We study normal CR compact manifolds in dimension 3. For a choice of a CR Reeb vector field, we associate a Sasakian metric on them, and we classify those metrics. As a consequence, the underlying manifolds are topologically finite quotiens of S or of a circle bundle over a Riemann surface of positive genus. In the latter case, we prove that their CR automorphisms group is a finite extension of...

Embedding 3-manifolds with Circle Actions in 4-space

We give constraints on the Seifert invariants of orientable 3-manifolds which admit fixed-point free circle actions and embed in R. In particular, the generalized Euler invariant ε of the orbit fibration is determined up to sign by the base orbifold B unless H1(M ;Z) is torsion free, in which case it can take at most one nonzero value (up to sign). No such manifold with base B = S2(α1, . . . , ...

Flats in 3-manifolds

— We prove that if a closed aspherical Riemannian 3-manifold M contains a 2-flat, then there exists a free abelian subgroup of rank two in π1(M). Under some restrictions on the topology of M we prove the existence of an immersed incompressible flat torus in M . This generalizes results which were previously known for manifolds of nonpositive curvature. RÉSUMÉ. — Nous prouvons que si une variété...