We use reduced homogeneous coordinates to study Riemannian geometry of the octonionic (or Cayley) projective plane. Our method extends to the para-octonionic (or split octonionic) projective plane, the octonionic projective plane of indefinite signature, and the hyperbolic dual of the octonionic projective plane; we di…
Study of SL(2) over octonions using twistor geometry.
problem No invertible 2x2 matrices over octonions, use Spin(9,1) x SL(2,R) orbit.
method Twistor geometry in eight dimensions.
result Interpretation of open orbit in 32D representation space.
Construct Clifford systems on Euclidean spaces and manifolds.
problem No specific problem stated; general Clifford systems construction.
method Inductive construction and adaptation to manifolds.
result Developments in octonionic geometry.
Reviews interactions between Spin(9) and octonionic geometries.
problem Understanding the role of Spin(9) in octonionic geometry.
method Analyzes canonical 8-forms, vector fields, Hopf fibrations, and manifolds.
result Discovers new insights into the geometry of octonionic Hopf fibrations.
New octonionic Kähler metrics solve an octonionic Calabi-Yau theorem.
problem Finding metrics on 16D manifolds.
method Introduced octonionic Kähler metrics and solved an octonionic Monge-Ampère equation.
result Solved an octonionic Calabi-Yau theorem.
Abstract: Investigates octonion product deformations and related geometries.
problem Exploring geometries and deformations from the 7-sphere S7. method Analyzing the spontaneous compactification M4imesS7 and solutions of Lagrangian equations. result Obtains a family of geometries including those with torsion and G2-structures. The dimensions of the spaces of k-homogeneous Spin(9)-invariant valuations on the octonionic plane are computed using results from the theory of differential forms on contact manifolds as well as octonionic geometry and representation theory. Moreover, a valuation on Riemannian manifolds of particular inte…
This paper is devoted to the specific class of pseudoconformal mappings of quaternion and octonion variables. Normal families of functions are defined and investigated. Four criteria of a family being normal are proven. Then groups of pseudoconformal diffeomorphisms of quaternion and octonion manifolds are investigated…
Understanding the exceptional Lie groups as the symmetry groups of simpler objects is a long-standing program in mathematics. Here, we explore one famous realization of the smallest exceptional Lie group, G2. Its Lie algebra acts locally as the symmetries of a ball rolling on a larger ball, but only when the ratio of r…
Introduction to G2 geometry for beginners.
problem Understanding G2 geometry and its special algebraic structure.
method Informal introduction with emphasis on octonions and linear algebra.
result Explains the special linear algebraic structure in 7 dimensions.
A theorem of Lawson and Simons states that the only stable minimal submanifolds in complex projective spaces are complex submanifolds. We generalize their result to the cases of quaternionic and octonionic projective spaces. Our approach gives a unified viewpoint towards conformal and projective geometries.
We deal with Riemannian properties of the octonionic Hopf fibration S^{15}-->S^8, in terms of the structure given by its symmetry group Spin(9). In particular, we show that any vertical vector field has at least one zero, thus reproving the non-existence of S^1 subfibrations. We then discuss Spin(9)-structures from a c…
This is an expository paper. Its purpose is to explain the linear algebra that underlies Donaldson-Thomas theory and the geometry of Riemannian manifolds with holonomy in G2 and Spin(7).
Research examines octonionic slice regular functions and their automorphisms and invariants.
problem Analyzing slice regular functions in the octonionic algebra.
method Investigates automorphisms and invariants of octonionic slice regular functions.
result Characterizes the automorphisms and invariants of octonionic slice regular functions.
The abstract defines G2-structures and connects them to octonion algebras.
problem Classifying G2-structures and understanding their geometric properties. method Established an isomorphism between G2-structures and octonion algebras over C∞(M). result The classification of G2-structures agrees with a parametrisation of octonion algebras with isometric norm. Combinatorial proof confirms two exceptional compact Tits geometries of type C3 are simply connected.
problem Proving two exceptional compact Tits geometries of type C3 are simply connected.
method Combinatorial proof independent of Kramer and Lytchak's result.
result Two exceptional compact Tits geometries of type C3 are simply connected.
We use a G2-structure on a 7-dimensional Riemannian manifold with a fixed metric to define an octonion bundle with a fiberwise non-associative product. We then define a metric-compatible octonion covariant derivative on this bundle that is compatible with the octonion product. The torsion of the G2-structure is then sh…
Study on octonionic Nahm's equations and their moduli space properties.
problem Properties of octonionic Nahm's equations and their moduli space.
method Analyzing basic properties, constructing solutions, introducing symmetry, proving theorems.
result Moduli space of smooth solutions to octonionic Nahm's equations over [0,1] is a star-shaped smooth manifold.
Introduces Plücker coordinates for a complex projective octonion plane, solving an overdetermined system of relations.
problem Understanding the complex projective octonion plane and its quotient space EIII.
method Introduces Plücker coordinates and uses Clifford algebra to solve the overdetermined system of relations.
result Shows that EIII can be decomposed into F4-orbits and provides detailed analysis near the subvariety X∞.
Study subelliptic heat kernel on octonionic anti-de Sitter space.
problem Heat kernel of octonionic anti-de Sitter space.
method Lift Laplacian of octonionic hyperbolic space and use sub-Laplacian.
result Two integral representations for subelliptic heat kernel.
Constructs projective plane over octonions, proving no higher real division algebras.
problem Existence of higher-dimensional real division algebras.
method Using Adams' solution of the Hopf invariant 1 problem, constructs projective plane over octonions.
result No higher-dimensional real division algebras exist.
The paper explores spinors and polyforms using quaternions and octonions.
problem Understanding spinors and polyforms in Clifford algebras.
method Generalizes Pauli matrices to quaternions and octonions, and relates these to spinor models.
result Explicitly describes Weyl spinors of Spin(4,4) related to quaternions and octonions.
New mechanics on non-associative octonions discovered.
problem Discrete mechanics on non-associative groups.
method Generalized Lagrangian and Hamiltonian mechanics to non-associative objects.
result Discrete mechanics on unitary octonions achieved.
James's octonionic Stiefel spaces questions answered partially.
problem Two fundamental questions about octonionic Stiefel spaces.
method Partial answers to James's questions about octonionic Stiefel spaces.
result Partial answers to James's questions about octonionic Stiefel spaces.
Many quantum groups and quantum spaces of interest can be obtained by cochain (but not cocycle) twist from their corresponding classical object. This failure of the cocycle condition implies a hidden nonassociativity in the noncommutative geometry already known to be visible at the level of differential forms. We exten…
We prove that Riemannian Spin(7) holonomy manifolds carry octonionic-Kähler structure.
The aim of this article is the proof of the following result: Let M be a connected manifold endowed with a regular Cartan geometry modelled on the boundary X of the d-dimensional real (resp. complex, resp. quaternionic, resp. octonionic) hyperbolic space. If the group of automorphisms of M does not act properly on M, t…
Minimal submanifolds in octonionic hyperbolic spaces have large volume.
problem Characterizing minimal submanifolds in locally symmetric spaces.
method Analyzing higher expansion properties and volume constraints.
result Codimension two minimal submanifolds have at least linear volume in the ambient space.
Study subelliptic heat kernel on lifted sphere from octonionic projective space.
problem Analyzing sub-Laplacian on lifted sphere from octonionic projective space.
method Explicit formulas for heat kernel and Green function derived.
result Explicit formulas for heat kernel and Green function.
New formula found for a unique invariant 8-form on Riemannian manifolds with Spin(9) structure.
problem Finding a new explicit algebraic formula for a unique invariant 8-form.
method Generalizing the standard Kähler 2-form expression, constructing the invariant 8-form from octonion-valued coordinate 1-forms.
result A new explicit algebraic formula for the Spin(9)-invariant 8-form. We show that any dimension 6 nearly Kähler (or nearly para-Kähler) geometry arises as a projective manifold equipped with a G2(∗) holonomy reduction. In the converse direction we show that if a projective manifold is equipped with a parallel 7-dimensional cross product on its standard tractor bundle …
Let M be either a simply connected pseudo-Riemannian space of constant curvature or a rank one Riemannian symmetric space (other than the octonion hyperbolic plane), and consider the space L(M) of oriented geodesics of M. The space L(M) is a smooth homogeneous manifold and in this paper we describe all invariant symple…
Study of a G2-equivariant octonionic operator and its right spectrum.
problem Understanding the spectrum of a G2-equivariant octonionic operator. method Computed the ordinary real spectrum and analyzed the octonionic right-eigenvalue problem using G2-decomposition and residual symmetry analysis. result Explicit spectral loci (quartic curve and circle) in each complex slice of the octonionic space.
We develop and study quaternionic and octonionic analogies of Cartan angular and Toledo invariants that are well known in the complex hyperbolic space. Using such invariants we study quasifuchsian deformations (including bendings) of quaternionic and octonionic hyperbolic manifolds.
634 vertex-transitive and over 10^103 non-vertex-transitive 27-vertex triangulations of octonionic projective plane.
problem Constructing and classifying triangulations of the octonionic projective plane.
method Combinatorial construction and analysis of symmetry groups.
result Found 634 vertex-transitive and over 10^103 non-vertex-transitive 27-vertex triangulations.
We use the octonion algebra to construct singular solutions of Hessian fully nonlinear uniformly elliptic equations in 21 or more dimensions. The regularity of these solutions is the least possible one. The same is proven for Isaacs equtions.
The paper defines and characterizes 2-Ruled hypersurfaces in Minkowski 4-space using octonions.
problem Characterizing 2-Ruled hypersurfaces in Minkowski 4-space.
method Definition and analysis of 2-Ruled hypersurfaces using octonions.
result Characterizations of Gaussian and mean curvatures of 2-Ruled hypersurfaces.
The study finds Lie algebra formulae and classifies polar actions on a hyperbolic plane.
problem Finding Lie algebra formulae and classifying actions on hyperbolic planes.
method Using octonions and triality, explicit Lie brackets were found for Lie algebras of isometry groups.
result Explicit formulae for Lie brackets of f4 and f4∗ Lie algebras. Maps from 2-planes to projective spaces using quaternions and octonions.
problem Constructing maps between geometric spaces.
method Using quaternions and octonions, maps are constructed from Gr2(Rn) to RPk. result Maps induce isomorphisms at the fundamental group level and are submersions for certain values of n and k. Study G2-structures in N=1 AdS4 solutions of M-theory.
problem Characterize G2-structures in N=1 AdS4 solutions of M-theory.
method Reformulate Killing spinor equations using octonion bundle structure; study G2-structures and their torsion.
result Define single complexified G2-structure or two real G2-structures on M.
Researchers describe even Clifford structures on specific Grassmannians.
problem Understanding even Clifford structures on Grassmannians.
method Explicit description of structures on real, complex, and quaternionic Grassmannians.
result Explicit description of non-flat parallel even Clifford structures of ranks 8, 6, and 5.
We develop a unifed theory to study geometry of manifolds with different holonomy groups. They are classified by (1) real, complex, quaternion or octonion number they are defined over and (2) being special or not. Specialty is an orientation with respect to the corresponding normed algebra A. For example, special Riema…
Special orthogonal representations from octonions have geometric properties linked to binary cubics.
problem Understanding geometric properties of special orthogonal representations from octonions.
method Using octonions and their derivations, spinors, and covariants to show geometric properties.
result Covariants and Mathews identities of these representations are related to the Fano plane and (Z2)3. Equations found for a special geometric space.
problem Defining equations for a specific geometric space.
method Study of torus fixed points to compute Poincaré polynomial.
result Poincaré polynomial computed for the compactification.
Extends potential theory to Carnot groups, estimating Hausdorff dimension.
problem Estimating Hausdorff dimension of polar sets in Carnot groups.
method Geometric completeness and Riesz potential inequalities in Carnot groups.
result Developed applications in CR geometry and quaternionic CR geometry.
Formula derived for Lie algebra E8's bracket.
problem Calculating the bracket of the exceptional Lie algebra E8.
method Based on triality and oct-octonions, following Barton-Sudbery description.
result Explicit formula for E8's bracket.
Stable planes are locally isomorphic to classical projective planes.
problem Characterizing stable planes that are locally isomorphic to classical projective planes.
method Analyzing properties of stable planes and comparing them to classical projective planes over specific fields.
result Simply connected stable planes with connected lines are isomorphic to open subplanes of classical projective planes.
Study of Schrödinger flows on S6 using octonions.
problem Schrödinger flows on S6 and related geometric properties. method Using G2-structure on O, study of G2-binormal motion of curves in R7. result Equivalence of G2-binormal motion to Schrödinger flows and nonlinear Schrödinger-type system.