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In this paper, the theory of functions of one complex variable is explored to study linearly full unramified holomorphic two-spheres with constant curvature in $G(2,n)$ satisfying that the generated harmonic sequence degenerates at position…

Differential Geometry · Mathematics 2020-03-06 Jie Fei , Ling He

Wave maps (or Lorentzian-harmonic maps) from a $1+1$-dimensional Lorentz space into the $2$-sphere are associated to constant negative Gaussian curvature surfaces in Euclidean 3-space via the Gauss map, which is harmonic with respect to the…

Differential Geometry · Mathematics 2020-02-03 David Brander , Farid Tari

Weighted cup-length calculations in singular cohomology led Farber and Grant in 2008 to general lower bounds for the topological complexity of lens spaces. We replace singular cohomology by K-theory, and weighted cup-length arguments by…

Algebraic Topology · Mathematics 2013-01-01 Jesus Gonzalez , Maurilio Velasco , W. Stephen Wilson

For dimensions $n\geq 3$ and $k\in\{2, \cdots, n\}$, we show that the space of metrics of $k$-positive Ricci curvature on the sphere $S^{n}$ has the structure of an $H$-space with a homotopy commutative, homotopy associative product…

Differential Geometry · Mathematics 2020-08-28 Mark Walsh , David J. Wraith

The author has already proven that the space $\Delta(\Pi_n)/G$ is homotopy equivalent to a wedge of spheres of dimension $n-3$ for all natural numbers $n\geq 3$ and all subgroups $G\subset S_1\times S_{n-1}$. We construct an $S_1\times…

Algebraic Topology · Mathematics 2020-09-29 Ralf Donau

Let $S$ be a complete flat surface, such as the Euclidean plane. We determine the homeomorphism class of the space of all curves on $S$ which start and end at given points in given directions and whose curvatures are constrained to lie in a…

Geometric Topology · Mathematics 2025-10-28 Nicolau C. Saldanha , Pedro Zühlke

We study questions of the following type: Can one assign continuously and $\Sigma_m$-equivariantly to any $m$-tuple of distinct points on the sphere $S^n$ a multipath in $S^n$ spanning these points? A \emph{multipath} is a continuous map of…

Algebraic Topology · Mathematics 2012-03-05 Roman Karasev , Peter Landweber

Motivated by the recent work of Algom-Kfir and Bestinva introducing the mapping class group of an infinite graph via proper homotopy equivalences, we give a necessary and sufficient condition for a surface to be properly homotopy equivalent…

Geometric Topology · Mathematics 2024-10-29 Ryan Dickmann , Hannah Hoganson , Sanghoon Kwak

We construct, for every even dimensional sphere $S^n$, $n >1$, and every odd integer $k$, a homogeneous polynomial map $f: S^{n}\to S^{n}$ of Brouwer degree $k$ and algebraic degree $2|k|-1$.

Algebraic Topology · Mathematics 2007-05-23 Javier Turiel

we study the exponential map for A_n = R^2^n, the Cayley_Dickson algebras for n bigher than 1,wich generalize the Complex exponential map to Quaternions,Octonions and so forth. As application,we show that the self-map of the unit sphere in…

Quantum Algebra · Mathematics 2007-05-23 Guillermo Moreno

Let M be a simply-connected closed oriented N-dimensional manifold. We prove that for any field of coefficients there exists a natural homomorphism of commutative graded algebras $\Psi : H_\ast (\Omega {aut}_1 M) \to H_{\ast +N}(M^{S^1})$…

Algebraic Topology · Mathematics 2007-05-23 Yves Felix , Jean-Claude Thomas

In this paper we consider the Balmu\c{s}-Montaldo-Oniciuc's conjecture in the case of hemispheres. We prove that a compact non-minimal biharmonic hypersurface in a hemisphere of $S^{n+1}$ must be the small hypersphere…

Differential Geometry · Mathematics 2020-11-03 Matheus Vieira

For $N \geq 4$ we classify the $(N-3)$-degenerate smooth CR maps of the three-dimensional unit sphere into the $(2N-1)$-dimensional unit sphere. Each of these maps has image being contained in a five-dimensional complex-linear space and is…

Complex Variables · Mathematics 2024-04-29 Giuseppe della Sala , Bernhard Lamel , Michael Reiter , Duong Ngoc Son

This paper is on homotopy classification of maps of (n+1)-dimensional manifolds into the n-dimensional sphere. For a continuous map f of an (n+1)-manifold into the n-sphere define the degree deg f to be the class dual to f^*[S^n], where…

Geometric Topology · Mathematics 2013-05-24 Dušan Repovš , Mikhail Skopenkov , Fulvia Spaggiari

This paper addresses the challenge of spectral analysis and structural investigation for graphs that are not distance-regular, where computing the spectrum using standard methods based on equitable and orbit partitions can be complex. Our…

Combinatorics · Mathematics 2025-11-26 Ali Zafari , Saeid Alikhani

In this manuscript we study rotationally $p$-harmonic maps between spheres. We prove that for $p\in\mathbb{N}$ given, there exist infinitely many $p$-harmonic self-maps of $\mathbb{S}^m$ for each $m\in\mathbb{N}$ with $p<m< 2+p+2\sqrt{p}$.…

Differential Geometry · Mathematics 2022-08-02 Volker Branding , Anna Siffert

Many important equations of mathematical physics arise geometrically as geodesic equations on Lie groups. In this paper, we study an example of a geodesic equation, the two-component Hunter-Saxton (2HS) system, that displays a number of…

Differential Geometry · Mathematics 2013-03-25 Jonatan Lenells

We discuss generic smooth maps from smooth manifolds to smooth surfaces, which we call "Morse 2-functions", and homotopies between such maps. The two central issues are to keep the fibers connected, in which case the Morse 2-function is…

Geometric Topology · Mathematics 2016-07-13 David T. Gay , Robion Kirby

In a well known work [Se], Graeme Segal proved that the space of holomorphic maps from a Riemann surface to a complex projective space is homology equivalent to the corresponding continuous mapping space through a range of dimensions…

Symplectic Geometry · Mathematics 2014-10-01 Jeremy Miller

Starting with an O(2)-principal fibration over a closed oriented surface F_g, g>=1, a 2-fold covering of the total space is said to be special when the monodromy sends the fiber SO(2) = S^1 to the nontrivial element of Z_2. Adapting D…

Algebraic Topology · Mathematics 2009-04-08 Anne Bauval , Daciberg L Goncalves , Claude Hayat , Maria Herminia de Paula Leite Mello