scholarly journals Real hypersurfaces in the complex projective plane satisfying an equality involving $\delta(2)$

Author(s):  
T. SASAHARA
Author(s):  
Theocharis Theofanidis

Real hypersurfaces satisfying the conditionϕl=lϕ(l=R(·,ξ)ξ)have been studied by many authors under at least one more condition, since the class of these hypersurfaces is quite tough to be classified. The aim of the present paper is the classification of real hypersurfaces in complex projective planeCP2satisfying a generalization ofϕl=lϕunder an additional restriction on a specific function.


2015 ◽  
Vol 12 (08) ◽  
pp. 1560013 ◽  
Author(s):  
J. Carlos Díaz Ramos ◽  
Cristina Vidal-Castiñeira

We give examples of real hypersurfaces with two distinct principal curvatures in the complex projective plane ℂP2.


Author(s):  
Grzegorz Malara ◽  
Piotr Pokora ◽  
Halszka Tutaj-Gasińska

AbstractIn this note we study curves (arrangements) in the complex projective plane which can be considered as generalizations of free curves. We construct families of arrangements which are nearly free and possess interesting geometric properties. More generally, we study 3-syzygy curve arrangements and we present examples that admit unexpected curves.


Author(s):  
Loring W. Tu

This chapter focuses on spectral sequences. The spectral sequence is a powerful computational tool in the theory of fiber bundles. First introduced by Jean Leray in the 1940s, it was further refined by Jean-Louis Koszul, Henri Cartan, Jean-Pierre Serre, and many others. The chapter provides a short introduction, without proofs, to spectral sequences. As an example, it computes the cohomology of the complex projective plane. The chapter then details Leray's theorem. A spectral sequence is like a book with many pages. Each time one turns a page, one obtains a new page that is the cohomology of the previous page.


2020 ◽  
Vol 71 (3) ◽  
pp. 997-1007
Author(s):  
Brendan Owens

Abstract We exhibit an infinite family of rational homology balls, which embed smoothly but not symplectically in the complex projective plane. We also obtain a new lattice embedding obstruction from Donaldson’s diagonalization theorem and use this to show that no two of our examples may be embedded disjointly.


1997 ◽  
Vol 40 (3) ◽  
pp. 285-295 ◽  
Author(s):  
T. Arleigh Crawford

AbstractIn this paper we study the topology of the space of harmonic maps from S2 to ℂℙ2.We prove that the subspaces consisting of maps of a fixed degree and energy are path connected. By a result of Guest and Ohnita it follows that the same is true for the space of harmonic maps to ℂℙn for n ≥ 2. We show that the components of maps to ℂℙ2 are complex manifolds.


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