scholarly journals Classification of non-Kähler surfaces and locally conformally Kähler geometry

2021 ◽  
Vol 76 (2) ◽  
Author(s):  
Mikhail Sergeevich Verbitsky ◽  
Victor Vuletescu ◽  
Liviu Ornea
Keyword(s):  
Kahler Geometry ◽  
Kähler Surfaces ◽  
Locally Conformally Kähler

scholarly journals On the Classification of ALE Kähler Manifolds

2020 ◽  
Author(s):  
Hans-Joachim Hein ◽  
Rareş Răsdeaconu ◽  
Ioana Şuvaina
Keyword(s):  
Complex Structure ◽  
Kähler Manifold ◽  
Kähler Manifolds ◽  
Kahler Manifolds ◽  
Quotient Singularity ◽  
Kahler Manifold ◽  
Kähler Surfaces

Abstract The underlying complex structure of an ALE Kähler manifold is exhibited as a resolution of a deformation of an isolated quotient singularity. As a consequence, there exist only finitely many diffeomorphism types of minimal ALE Kähler surfaces with a given group at infinity.

PROJECTIVELY FLAT SURFACES AND BOGOMOLOV'S THEOREM ON CLASS VII0 SURFACES

1994 ◽  
Vol 05 (02) ◽  
pp. 253-264 ◽  
Author(s):  
ANDREI-DUMITRU TELEMAN
Keyword(s):  
Conformally Flat ◽  
Complete Proof ◽  
Flat Surfaces ◽  
Hermitian Surface ◽  
Projectively Flat ◽  
Locally Conformally Flat ◽  
Kähler Surfaces ◽  
Topological Character

We give a complete proof of Bogomolov's theorem on class VII 0 surfaces starting with the idea of Li, Yau and Zheng to use Kobayashi-Hitchin correspondence. We show that, because of the non-topological character of Gauduchon's degree, the proof of these authors is not complete. We prove that any projectively flat hermitian surface is locally conformally flat-Kähler, which reduces the problem to the classification of locally conformally flat-Kähler surfaces.

scholarly journals EXACT LOW-ENERGY EFFECTIVE ACTIONS FOR HYPERMULTIPLETS IN FOUR DIMENSIONS

2000 ◽  
Vol 15 (17) ◽  
pp. 2661-2713
Author(s):  
SERGEI V. KETOV
Keyword(s):  
Low Energy ◽  
Nonlinear Sigma Model ◽  
Kahler Geometry ◽  
Harmonic Superspace ◽  
N Transformations ◽  
Four Dimensions ◽  
Supersymmetric Gauge ◽  
Supersymmetric Nonlinear Sigma Model ◽  
Quartic Polynomials

We consider the general hypermultiplet low-energy effective action (LEEA) that may appear in quantized, four-dimensional, N=2 supersymmetric, gauge theories, e.g. in the Coulomb and Higgs branches. Our main purpose is a description of the exact LEEA of n magnetically charged hypermultiplets. The hypermultiplet LEEA is given by the N=2 supersymmetric nonlinear sigma-model (NLSM) with a 4n-dimensional hyper-Kähler metric, subject to nonanomalous symmetries. Harmonic superspace (HSS) and the NLSM isometries are very useful to constrain the hyper-Kähler geometry of the LEEA. We use N=2 supersymmetric projections of HSS superfields to N=2 linear (tensor) O(2) and O(4) multiplets in N=2projective superspace (PSS) to deduce the explicit form of the LEEA in some particular cases. As the by-product, a simple new classification of all multimonopole moduli space metrics having su (2)R symmetry is proposed in terms of real quartic polynomials of 2n variables, modulo Sp (n) transformations. The 4d hypermultiplet LEEA for n=2 can be encoded in terms of an elliptic curve.

scholarly journals HOMOGENEOUS SASAKI AND VAISMAN MANIFOLDS OF UNIMODULAR LIE GROUPS

2019 ◽  
pp. 1-14
Author(s):  
D. ALEKSEEVSKY ◽  
K. HASEGAWA ◽  
Y. KAMISHIMA
Keyword(s):  
Lie Groups ◽  
Special Kind ◽  
Basic Structure ◽  
Complete Classification ◽  
Locally Conformally Kähler ◽  
Vaisman Manifold ◽  
Simply Connected ◽  
Sasaki Manifold ◽  
Vaisman Manifolds

A Vaisman manifold is a special kind of locally conformally Kähler manifold, which is closely related to a Sasaki manifold. In this paper, we show a basic structure theorem of simply connected homogeneous Sasaki and Vaisman manifolds of unimodular Lie groups, up to holomorphic isometry. For the case of unimodular Lie groups, we obtain a complete classification of simply connected Sasaki and Vaisman unimodular Lie groups, up to modification.

Note on the spectral classification of carbon stars in the photographic infrared region

1966 ◽  
Vol 24 ◽  
pp. 21-23
Author(s):  
Y. Fujita
Keyword(s):  
Infrared Region ◽  
Spectral Classification ◽  
Carbon Stars

We have investigated the spectrograms (dispersion: 8Å/mm) in the photographic infrared region fromλ7500 toλ9000 of some carbon stars obtained by the coudé spectrograph of the 74-inch reflector attached to the Okayama Astrophysical Observatory. The names of the stars investigated are listed in Table 1.

Diagnostic Value of Electron Microscopy in Soft Tissue Tumors

1970 ◽  
Vol 28 ◽  
pp. 220-221
Author(s):  
Gerald Fine ◽  
Azorides R. Morales
Keyword(s):  
Cardiac Myxoma ◽  
Osteogenic Sarcoma ◽  
Diagnostic Value ◽  
Soft Tissue Tumors ◽  
Amelanotic Melanoma ◽  
Growth Patterns ◽  
Light Microscopic Level ◽  
Mesenchymal Tumors ◽  
Good Agreement

For years the separation of carcinoma and sarcoma and the subclassification of sarcomas has been based on the appearance of the tumor cells and their microscopic growth pattern and information derived from certain histochemical and special stains. Although this method of study has produced good agreement among pathologists in the separation of carcinoma from sarcoma, it has given less uniform results in the subclassification of sarcomas. There remain examples of neoplasms of different histogenesis, the classification of which is questionable because of similar cytologic and growth patterns at the light microscopic level; i.e. amelanotic melanoma versus carcinoma and occasionally sarcoma, sarcomas with an epithelial pattern of growth simulating carcinoma, histologically similar mesenchymal tumors of different histogenesis (histiocytoma versus rhabdomyosarcoma, lytic osteogenic sarcoma versus rhabdomyosarcoma), and myxomatous mesenchymal tumors of diverse histogenesis (myxoid rhabdo and liposarcomas, cardiac myxoma, myxoid neurofibroma, etc.)

Ultrastructure of mesotheliomas

1984 ◽  
Vol 42 ◽  
pp. 98-101
Author(s):  
Irving Dardick
Keyword(s):  
Electron Microscopy ◽  
Latent Period ◽  
Spindle Cell ◽  
Spindle Cell Sarcoma ◽  
Metastatic Adenocarcinoma ◽  
Cell Sarcoma ◽  
Cytological Features ◽  
Industrial Use ◽  
Degree Of Differentiation

With the extensive industrial use of asbestos in this century and the long latent period (20-50 years) between exposure and tumor presentation, the incidence of malignant mesothelioma is now increasing. Thus, surgical pathologists are more frequently faced with the dilemma of differentiating mesothelioma from metastatic adenocarcinoma and spindle-cell sarcoma involving serosal surfaces. Electron microscopy is amodality useful in clarifying this problem.In utilizing ultrastructural features in the diagnosis of mesothelioma, it is essential to appreciate that the classification of this tumor reflects a variety of morphologic forms of differing biologic behavior (Table 1). Furthermore, with the variable histology and degree of differentiation in mesotheliomas it might be expected that the ultrastructure of such tumors also reflects a range of cytological features. Such is the case.

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