activity
19972005
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6 papers · 1 filter

math.GT2005

Casson--type invariants in dimension four

Daniel Ruberman, Nikolai Saveliev

This article surveys our ongoing project about the relationship between invariants extending the classical Rohlin invariant of homology spheres and those coming from 4-dimensional…

math.GT2003

Rohlin's invariant and gauge theory, I. Homology 3-tori

Daniel Ruberman, Nikolai Saveliev

This is the first in a series of papers exploring the relationship between the Rohlin invariant and gauge theory. We discuss the Casson-type invariant of a 3-manifold with the inte…

math.GT2002

The Seiberg-Witten invariants of manifolds with wells of negative curvature

Daniel Ruberman

We extend the vanishing theorem for the Seiberg-Witten invariants of a manifold with positive scalar curvature to the case when the curvature is allowed to be negative on a set of…

math.GT2000

Embedding tangles in links

Daniel Ruberman

We reprove and extend a result of David Krebes (J. Knot Theory Ramif. 8 (1999), 321-352) giving an obstruction to embedding a tangle T into a link L. Closing the tangle up in the t…

math.GT1998

An obstruction to smooth isotopy in dimension 4

Daniel Ruberman

Techniques of gauge theory are used to define and compute an invariant of certain diffeomorphisms of 4-manifolds. The invariant vanishes for any diffeomorphism which is smoothly is…

math.GT1997

Isospectrality and 3-manifold groups

Daniel Ruberman

The relationship between the Chern-Simons invariant and eta-invariant of a 3-manifold is shown to lead to an obstruction to a group being the fundamental group of a closed oriented…