88 citations · 276 across the 10 of their papers we have counts for
13 papers
Cohomogeneity-one solitons in Laplacian flow: local, smoothly-closing and steady solitons
Mark Haskins, Johannes Nordström
We initiate a systematic study of cohomogeneity-one solitons in Bryant's Laplacian flow of closed G_2-structures on a 7-manifold, motivated by the problem of understanding finite-t…
Nu-invariants of extra-twisted connected sums
Sebastian Goette, Johannes Nordström, Don Zagier
We analyse the possible ways of gluing twisted products of circles with asymptotically cylindrical Calabi-Yau manifolds to produce manifolds with holonomy G_2, thus generalising th…
Complete non-compact G2-manifolds from asymptotically conical Calabi-Yau 3-folds
Lorenzo Foscolo, Mark Haskins, Johannes Nordström
We develop a powerful new analytic method to construct complete non-compact G2-manifolds, i.e. Riemannian 7-manifolds (M,g) whose holonomy group is the compact exceptional Lie grou…
Construction of G_2-instantons via twisted connected sums
Grégoire Menet, Johannes Nordström, Henrique N. Sá Earp
We propose a method to construct G_2-instantons over a compact twisted connected sum G_2-manifold, applying a gluing result of Sá Earp and Walpuski to instantons over a pair of 7-m…
The rational homotopy type of (n-1)-connected manifolds of dimension up to 5n-3
Diarmuid Crowley, Johannes Nordström
We define the Bianchi-Massey tensor of a topological space X to be a linear map from a subquotient of the fourth tensor power of H*(X). We then prove that if M is a closed (n-1)-co…
An analytic invariant of G_2 manifolds
Diarmuid Crowley, Sebastian Goette, Johannes Nordström
We prove that the moduli space of holonomy G_2-metrics on a closed 7-manifold is in general disconnected by presenting a number of explicit examples. We detect different connected…
Exotic G_2-manifolds
Diarmuid Crowley, Johannes Nordström
We exhibit the first examples of closed 7-dimensional Riemannian manifolds with holonomy G_2 that are homeomorphic but not diffeomorphic. These are also the first examples of close…
The classification of 2-connected 7-manifolds
Diarmuid Crowley, Johannes Nordström
We present a classification theorem for closed smooth spin 2-connected 7-manifolds M. This builds on the almost-smooth classification from the first author's thesis. The main addit…
Asymptotically cylindrical Calabi-Yau manifolds
Mark Haskins, Hans-Joachim Hein, Johannes Nordström
Let be a complete Ricci-flat Kahler manifold with one end and assume that this end converges at an exponential rate to for some compact connected Ricci-fl…
New invariants of G_2-structures
Diarmuid Crowley, Johannes Nordström
We define a Z/48-valued homotopy invariant nu of a G_2-structure on the tangent bundle of a closed 7-manifold in terms of the signature and Euler characteristic of a coboundary wit…
G_2-manifolds and associative submanifolds via semi-Fano 3-folds
Alessio Corti, Mark Haskins, Johannes Nordström +1
We provide a significant extension of the twisted connected sum construction of G_2-manifolds, i.e. Riemannian 7-manifolds with holonomy group G_2, first developed by Kovalev; alon…
Asymptotically cylindrical Calabi-Yau 3-folds from weak Fano 3-folds
Alessio Corti, Mark Haskins, Johannes Nordström +1
We prove the existence of asymptotically cylindrical (ACyl) Calabi-Yau 3-folds starting with (almost) any deformation family of smooth weak Fano 3-folds. This allow us to exhibit h…
Asymptotically cylindrical 7-manifolds of holonomy G_2 with applications to compact irreducible G_2-manifolds
Alexei Kovalev, Johannes Nordström
We construct examples of exponentially asymptotically cylindrical Riemannian 7-manifolds with holonomy group equal to G_2. To our knowledge, these are the first such examples. We a…