Julien Heyd

collaborators

3 papers

math.DG2024

Classification of Affinely Homogeneous Hessian Rank 2 Hypersurfaces S^3 in R^4

Julien Heyd, Joel Merker

We determine all affinely homogeneous hypersurfaces S^3 in R^4 whose Hessian is (invariantly) of constant rank 2, including the simply transitive ones. We find 34 inequivalent term…

math.DG2024

On Affinely Homogeneous Submanifolds: The Power Series Method of Equivalence

Julien Heyd, Joel Merker

We determine all affinely homogeneous models for surfaces $S^{2} \subset R^{4}$ , including the simply transitive models. We employ an improved power series method of equivalen…

math.DG2021

Normal Forms of second order Ordinary Differential Equations $y_{xx} = J (x, y, y_{x})$ under Fibre-Preserving Maps

Wei Guo Foo, Julien Heyd, Joël Merker

We study the equivalence problem of classifying second order ordinary differential equations $y_{xx} = J (x, y, y_{x})$ modulo fibre-preserving point transformations $x ⟼ φ (x)$ …

Classification of Affinely Homogeneous Hessian Rank 2 Hypersurfaces S^3 in R^4

On Affinely Homogeneous Submanifolds: The Power Series Method of Equivalence

Normal Forms of second order Ordinary Differential Equations yxx​=J(x,y,yx​) under Fibre-Preserving Maps

Normal Forms of second order Ordinary Differential Equations $y_{xx} = J (x, y, y_{x})$ under Fibre-Preserving Maps