16 citations · 23 across the 10 of their papers we have counts for
4 papers · 2 filters
Stabilisation, bordism and embedded spheres in 4--manifolds
Christian Bohr
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. Freedm…
Cycles, submanifolds, and structures on normal bundles
C. Bohr, B. Hanke, D. Kotschick
We give explicit examples of degree 3 cohomology classes not Poincare dual to submanifolds, and discuss the realisability of homology classes by submanifolds with Spin-C normal bun…
Immersions of surfaces in almost complex 4-manifolds
Christian Bohr
In this note, we investigate the relation between double points and complex points of immersed surfaces in almost-complex 4-manifolds and show how estimates for the minimal genus o…
On the signatures of even 4-manifolds
Christian Bohr
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…