Professor Norbert Peyerimhoff's Outputs (6)

Quartic graphs which are Bakry-Émery curvature sharp (2019)
Journal Article
Cushing, D., Kamtue, S., Peyerimhoff, N., & Watson May, L. (2020). Quartic graphs which are Bakry-Émery curvature sharp. Discrete Mathematics, 343(3), Article 111767. https://doi.org/10.1016/j.disc.2019.111767

We give a classification of all connected quartic graphs which are (infinity) curvature sharp in all vertices with respect to Bakry-Émery curvature. The result is based on a computer classification by F. Gurr and L. Watson May and a combinatorial cas... Read More about Quartic graphs which are Bakry-Émery curvature sharp.

The Fourier Transform on harmonic manifolds of purely exponential volume growth (2019)
Journal Article
Biswas, K., Knieper, G., & Peyerimhoff, N. (2021). The Fourier Transform on harmonic manifolds of purely exponential volume growth. Journal of Geometric Analysis, 31(1), 126-163. https://doi.org/10.1007/s12220-019-00253-9

Let X be a complete, simply connected harmonic manifold of purely exponential volume growth. This class contains all non-flat harmonic manifolds of non-positive curvature and, in particular all known examples of non-compact harmonic manifolds except... Read More about The Fourier Transform on harmonic manifolds of purely exponential volume growth.

Trivalent expanders, $(Delta – Y)$-transformation, and hyperbolic surfaces (2019)
Journal Article
Ivrissimtzis, I., Peyerimhoff, N., & Vdovina, A. (2019). Trivalent expanders, $(Delta – Y)$-transformation, and hyperbolic surfaces. Groups, Geometry, and Dynamics, 13(3), 1103-1131. https://doi.org/10.4171/ggd/518

We construct a new family of trivalent expanders tessellating hyperbolic surfaces with large isometry groups. These graphs are obtained from a family of Cayley graphs of nilpotent groups via (Delta–Y)-transformations. We study combinatorial, topologi... Read More about Trivalent expanders, $(Delta – Y)$-transformation, and hyperbolic surfaces.

A support theorem for the X-ray transform on manifolds with plane covers (2019)
Journal Article
Peyerimhoff, N., & Samiou, E. (2020). A support theorem for the X-ray transform on manifolds with plane covers. Mathematical Proceedings of the Cambridge Philosophical Society, 169(1), 149-158. https://doi.org/10.1017/s0305004119000148

This paper is concerned with support theorems of the X-ray transform on non-compact manifolds with conjugate points. In particular, we prove that all simply connected 2-step nilpotent Lie groups have a support theorem. Important ingredients of the pr... Read More about A support theorem for the X-ray transform on manifolds with plane covers.

Distance Bounds for Graphs with Some Negative Bakry-Émery Curvature (2019)
Journal Article
Liu, S., Münch, F., Peyerimhoff, N., & Rose, C. (2019). Distance Bounds for Graphs with Some Negative Bakry-Émery Curvature. Analysis and Geometry in Metric Spaces, 7(1), 1-14. https://doi.org/10.1515/agms-2019-0001

We prove distance bounds for graphs possessing positive Bakry-Émery curvature apart from an exceptional set, where the curvature is allowed to be non-positive. If the set of non-positively curved vertices is finite, then the graph admits an explicit... Read More about Distance Bounds for Graphs with Some Negative Bakry-Émery Curvature.

Curvature and higher order Buser inequalities for the graph connection Laplacian (2019)
Journal Article
Liu, S., Muench, F., & Peyerimhoff, N. (2019). Curvature and higher order Buser inequalities for the graph connection Laplacian. SIAM Journal on Discrete Mathematics, 33(1), 257-305. https://doi.org/10.1137/16m1056353

We study the eigenvalues of the connection Laplacian on a graph with an orthogonal group or unitary group signature. We establish higher order Buser type inequalities, i.e., we provide upper bounds for eigenvalues in terms of Cheeger constants in the... Read More about Curvature and higher order Buser inequalities for the graph connection Laplacian.