Do you want to publish a course? Click here

On the signatures of even 4-manifolds

127   0   0.0 ( 0 )
 Added by Christian Bohr
 Publication date 2000
  fields
and research's language is English




Ask ChatGPT about the research

In this paper, we prove a number of inequalities between the signature and the Betti numbers of a 4-manifold with even intersection form. Furthermore, we introduce a new geometric group invariant and discuss some of its properties.



rate research

Read More

We prove that for 4-manifolds $M$ with residually finite fundamental group and non-spin universal covering $Wi M$, the inequality $dim_{mc}Wi Mle 3$ implies the inequality $dim_{mc}Wi Mle 2$.
73 - Igor Nikolaev 2019
We construct a functor from the smooth 4-dimensional manifolds to the hyper-algebraic number fields, i.e. fields with non-commutative multiplication. It is proved that that the simply connected 4-manifolds correspond to the abelian extensions. We recover the Rokhlin and Donaldsons Theorems from the Galois theory of the non-commutative fields.
170 - Tadayuki Watanabe 2020
In this article, we construct countably many mutually non-isotopic diffeomorphisms of some closed non simply-connected 4-manifolds that are homotopic to but not isotopic to the identity, by surgery along $Theta$-graphs. As corollaries of this, we obtain some new results on codimension 1 embeddings and pseudo-isotopies of 4-manifolds. In the proof of the non-triviality of the diffeomorphisms, we utilize a twisted analogue of Kontsevichs characteristic class for smooth bundles, which is obtained by extending a higher dimensional analogue of March{e}--Lescops equivariant triple intersection in configuration spaces of 3-manifolds to allow Lie algebraic local coefficient system.
124 - Christian Bohr 2002
In this paper, we exploit a subtle indeterminacy in the definition of the spherical Kervaire-Milnor invariant which was discovered by R. Stong to construct non-spin 4-manifolds with even intersection form and prescribed signature.
94 - Christian Bohr 2000
It is one of the most important facts in 4-dimensional topology that not every spherical homology class of a 4-manifold can be represented by an embedded sphere. In 1978, M. Freedman and R. Kirby showed that in the simply connected case, many of the obstructions to constructing such a sphere vanish if one modifies the ambient 4-manifold by adding products of 2-spheres, a process which is usually called stabilisation. In this paper, we extend this result to non-simply connected 4-manifolds and show how it is related to the Spin^c-bordism groups of Eilenberg-MacLane spaces.
comments
Fetching comments Fetching comments
Sign in to be able to follow your search criteria
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا