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The doubling conjecture predicts that a manifold admits positive scalar curvature with mean convex boundary if and only if its double admits positive scalar curvature. We show that it holds true for manifolds where the inclusion of the…

Differential Geometry · Mathematics 2026-04-15 Georg Frenck

Positive curvature and bosons Compact positive curvature Riemannian manifolds M with symmetry group G allow Conner-Kobayashi reductions M to N, where N is the fixed point set of the symmetry G. The set N is a union of smaller-dimensional…

Mathematical Physics · Physics 2020-06-30 Oliver Knill

An upper bound is obtained on the rank of a torus which can act smoothly and effectively on a smooth, closed, simply connected, rationally elliptic manifold. In the maximal-rank case, the manifolds admitting such actions are classified up…

Differential Geometry · Mathematics 2020-03-24 Fernando Galaz-Garcia , Martin Kerin , Marco Radeschi

For Einstein four-manifolds with positive scalar curvature, we derive relations among various positivity conditions on the curvature tensor, some of which are of great importance in the study of the Ricci flow. These relations suggest…

Differential Geometry · Mathematics 2019-03-29 Peng Wu

We show that a closed simply connected 8-manifold (9-manifold) of positive sectional curvature on which a 3-torus (4-torus) acts isometrically is homeomorphic to a sphere, a complex projective space or a quaternionic projective plane…

Differential Geometry · Mathematics 2007-05-23 Fuquan Fang , Xiaochun Rong

We investigate asymptotically flat manifolds with cone structure at infinity. We show that any such manifold M has a finite number of ends. For simply connected ends we classify all possible cones at infinity, except for the 4-dimensional…

Differential Geometry · Mathematics 2016-07-22 Anton Petrunin , Wilderich Tuschmann

This is a survey on cohomogeneity one manifolds with positive curvature. We discuss the known examples of this type and their geometry and the functions that describe the metric. We also describe the classification of cohomogeneity one…

Differential Geometry · Mathematics 2007-07-24 Wolfgang Ziller

This paper deals with rational curves and birational contractions on irreducible holomorphically symplectic manifold. We survey some recent results about minimal rational curves, their deformations, extremal rays associated with these…

Algebraic Geometry · Mathematics 2020-11-18 Ekaterina Amerik , Misha Verbitsky

We prove a Riemannian positive mass theorem for manifolds with a single asymptotically flat end, but otherwise arbitrary other ends, which can be incomplete and contain negative scalar curvature. The incompleteness and negativity is…

Differential Geometry · Mathematics 2021-03-05 Martin Lesourd , Ryan Unger , Shing-Tung Yau

We show that a compact manifold admitting a Killing foliation with positive transverse curvature fibers over finite quotients of spheres or weighted complex projective spaces, provided that the singular foliation defined by the closures of…

Differential Geometry · Mathematics 2022-10-05 Francisco C. Caramello , Dirk Toeben

We formulate a conjecture relating the topology of a manifold's universal cover with the existence of metrics with positive $m$-intermediate curvature. We prove the result for manifolds of dimension $n\in\{3,4,5\}$ and for most choices of…

Differential Geometry · Mathematics 2025-03-19 Liam Mazurowski , Tongrui Wang , Xuan Yao

Using Quillen's superconnection formalism we give a new "twisted" approach to the rational Gromov-Lawson-Rosenberg (GLR) conjecture on topological obstructions to the existence of Riemannian metrics of positive scalar curvature on compact…

Differential Geometry · Mathematics 2012-01-20 Varghese Mathai

We give a characterization of closed, simply connected, rationally elliptic 6-manifolds in terms of their rational cohomology rings and a partial classification of their real cohomology rings. We classify rational, real and complex homotopy…

Algebraic Topology · Mathematics 2015-04-10 Martin Herrmann

We investigate the topology and geometry of compact submanifolds in space forms of nonnegative curvature that satisfy a lower bound on the sectional curvature, depending only on the length of the mean curvature vector of the immersion. We…

Differential Geometry · Mathematics 2025-02-17 Theodoros Vlachos

We give the first examples of rationally inessential but macroscopically large manifolds. Our manifolds are counterexamples to the Dranishnikov rationality conjecture. For some of them we prove that they do not admit a metric of positive…

Geometric Topology · Mathematics 2016-03-01 Michał Marcinkowski

The Gromov-Lawson-Rosenberg conjecture for a group G states that a compact spin manifold with fundamental group G admits a metric of positive scalar curvature if and only if a certain topological obstruction vanishes. It is known to be true…

Algebraic Topology · Mathematics 2013-05-03 Arjun Malhotra

In this paper I present a comparison theorem for the waist of Riemannian manifolds with positive sectional curvature. The main theorem of this paper gives a partial positive answer to a conjecture formulated by M.Gromov in [8]. The content…

Metric Geometry · Mathematics 2013-12-04 Yashar Memarian

Let $X$ be a compact K\"ahler manifold. We prove that if $X$ admits a smooth Hermitian metric $\omega$ with quasi-positive second Chern-Ricci curvature $\mathrm{Ric}^{(2)}(\omega)$, then $X$ is projective and rationally connected. In…

Differential Geometry · Mathematics 2020-06-25 Xiaokui Yang

We extend two known existence results to simply connected manifolds with positive sectional curvature: we show that there exist pairs of simply connected positively-curved manifolds that are tangentially homotopy equivalent but not…

Differential Geometry · Mathematics 2020-08-19 David González-Álvaro , Marcus Zibrowius

We show the existence of metrically dense entire curves in rationally connected complex projective manifolds confirming for this case a conjecture according to which such entire curves on projective manifolds exist if and only if these are…

Algebraic Geometry · Mathematics 2020-01-09 Frederic Campana , Joerg Winkelmann